The best source of information for an IS auditor to use when determining whether an organization's information security policy is adequate is the risk assessment results. The risk assessment results provide the auditor with an overview of the organization's risk profile, including the identification, analysis, and evaluation of the risks that affect the confidentiality, integrity, and availability of the information assets. The auditor can use the risk assessment results to compare the organization's information security policy with the risk appetite, risk tolerance, and risk treatment strategies of the organization. The auditor can also use the risk assessment results to evaluate if the information security policy is aligned with the organization's objectives, requirements, and regulations.
Some of the web sources that support this answer are:
* Performance Measurement Guide for Information Security
* ISO 27001 Annex A.5 - Information Security Policies
* [CISA Certified Information Systems Auditor - Question0551]

An external assessment of network vulnerability is a process of identifying and evaluating the weaknesses and risks that affect the security and availability of a network from an outsider's perspective. The most important factor to verify during this process is the completeness of network asset inventory, which is a list of all the devices, systems, and software that are connected to or part of the network. A complete and accurate network asset inventory can help identify the scope and boundaries of the network, the potential attack vectors and entry points, the critical assets and dependencies, and the existing security controls and gaps. Without a complete network asset inventory, an external assessment of network vulnerability may miss some important assets or vulnerabilities, leading to inaccurate or incomplete results and recommendations.
References:
* 1 explains what is an external vulnerability scan and why it is important to have a complete network asset inventory.
* 2 provides a guide on how to conduct a full network vulnerability assessment and emphasizes the importance of knowing the network assets.
* 3 compares internal and external vulnerability scanning and highlights the need for a comprehensive network asset inventory for both types.

The best way to sanitize a hard disk for reuse to ensure the organization's information cannot be accessed is data wiping. Data wiping is a process that overwrites the data on the hard disk with random or meaningless patterns, making it unrecoverable by any software or hardware methods. Data wiping can provide a high level of security and assurance that the organization's information is permanently erased from the hard disk, and that it cannot be accessed by unauthorized parties or malicious actors.
Re-partitioning is not a way to sanitize a hard disk for reuse, but rather a way to organize the hard disk into different logical sections or volumes. Re-partitioning does not erase the data on the hard disk, but only changes the structure and allocation of the disk space. Re-partitioning may make the data inaccessible to the operating system, but not to other tools or methods that can scan or recover the data from the disk sectors.
Degaussing is a way to sanitize a hard disk for reuse, but only for magnetic hard disks, not solid state drives (SSDs). Degaussing is a process that exposes the hard disk to a strong magnetic field, which disrupts and destroys the magnetic alignment of the data on the disk platters. Degaussing can effectively erase the data on magnetic hard disks, but it can also damage or render unusable the electronic components of the hard disk, such as the read/write heads or circuit boards. Degaussing also does not work on SSDs, which store data using flash memory cells, not magnetic media.
Formatting is not a way to sanitize a hard disk for reuse, but rather a way to prepare the hard disk for use by an operating system. Formatting is a process that creates a file system on the hard disk, which defines how the data is stored and accessed on the disk. Formatting does not erase the data on the hard disk, but only deletes the file system metadata and marks the disk space as available for new data. Formatting may make the data invisible to the operating system, but not to other tools or methods that can restore or recover the data from the disk sectors.
References:
* How to Wipe A Hard Drive for Reuse? Check the Quickest Way to Wipe A Hard Drive - EaseUS 1
* HP PCs - Using Secure Erase or HP Disk Sanitizer 2
* HOW to QUICKLY and PERMANENTLY SANITIZE ANY DRIVE (SSD, USB thumb drive ...)

Section: Protection of Information Assets
Explanation:
The calculation of a hash, or digest, of the data that are transmitted and its encryption require the public key of the client (receiver) and is called a signature of the message, or digital signature.
The receiver performs the same process and then compares the received hash, once it has been decrypted with their private key, to the hash that is calculated with the received data. If they are the same, the conclusion would be that there is integrity in the data that have arrived and the origin is authenticated.
The concept of encrypting the hash with the private key of the originator provides non repudiation, as it can only be decrypted with their public key and, as the CD suggests, the private key would not be known to the recipient. Simply put, in a key-pair situation, anything that can be decrypted by a sender's public key must have been encrypted with their private key, so they must have been the sender, i.e., non-repudiation.
Choice C is incorrect because, if this were the case, the hash could not be decrypted by the recipient, so the benefit of non-repudiation would be lost and there could be no verification that the message had not been intercepted and amended. A digital signature is created by encrypting with a private key. A person creating the signature uses their own private key, otherwise everyone would be able to create a signature with any public key. Therefore, the signature of the client is created with the client's private key, and this can be verified-by the enterprise-using the client's public key. Choice B is the correct answer because, in this case, the customer uses their private key to sign the hash data.