Explanation
Capacity management tools are primarily used to ensure that available resources are used efficiently and effectively to meet the current and future demands of the business. Capacity management tools can help monitor, analyze and optimize the performance and utilization of IT resources such as CPU, memory, disk, network, etc. The other options are not the primary purpose of capacity management tools, although they may be related or derived from them. References:
ISACA, CISA Review Manual, 27th Edition, chapter 4, section 4.32
ISACA, COBIT 2019 Framework: Introduction and Methodology, section 3.2

The IS auditor should review the organization's patch management policy to determine the expected frequency and scope of patching, as well as the roles and responsibilities of the patch management team. This will help the auditor assess the severity and impact of the non-compliance, and identify the root cause and possible remediation actions12.
References
1: How to Create a Patch Management Policy: Complete Guide 2: Free Patch Management Policy Template (+Examples)

The correct answer is D. Recovery point objective (RPO) because the issue is related to data loss or data inconsistency after recovery, not simply the time taken to restore the database. RPO defines the point in time to which data must be recoverable after an outage or disruption. In practical terms, it answers: "How much data can the business afford to lose?" ISACA's contingency planning guidance explains that RPO represents the point in time prior to disruption to which business data can be recovered using the most recent backup, and it is directly related to the amount of data loss the business can tolerate.
The organization restored from the most recent available backup, but customers are reporting discrepancies.
This suggests the backup/recovery strategy may not meet the organization's acceptable data-loss requirement.
For example, if the business can tolerate losing only 15 minutes of transactions but backups are taken every
24 hours, recovered customer data may be outdated or incomplete. That is an RPO failure.
Option A is not the best answer because an SLA defines agreed service expectations, but the immediate audit concern is whether the backup point met the required data recovery point. Option B is not the best answer because MTO, also commonly discussed as maximum tolerable downtime, relates to the maximum outage period the business can tolerate, not the point to which data must be restored. Option C is not the best answer because RTO focuses on how quickly a system must be restored, while this case is about the correctness and completeness of recovered data.
This question maps mainly to Information Systems Operations and Business Resilience, because ISACA's CISA Exam Content Outline includes Database Management, Data Backup, Storage, and Restoration, Business Continuity Plan, and Disaster Recovery Plans under Domain 4.
References: ISACA CISA Exam Content Outline, Domain 4; ISACA Journal, Information System Contingency Planning Guidance.

A digital signature is a type of electronic signature that uses cryptographic techniques to provide authentication, integrity, and non-repudiation of digital documents. A digital signature is created by applying a mathematical function (called a hash function) to the document and then encrypting the result with the sender's private key. The encrypted hash, along with the sender's public key and other information, forms the digital signature. The receiver can verify the digital signature by decrypting it with the sender's public key and comparing the hash with the one computed from the document. If they match, it means that the document has not been altered and that it was signed by the owner of the private key.
Option D is correct because a digital signature is unique to the sender using it, as it depends on the sender's private key, which only the sender knows and controls. No one else can create a valid digital signature with the same private key, and no one can forge or modify a digital signature without being detected.
Option A is incorrect because a digital signature is not under control of the receiver, but rather under control of the sender. The receiver can only verify the digital signature, but cannot create or modify it.
Option B is incorrect because a digital signature is not capable of authorization, but rather capable of authentication. Authorization is the process of granting or denying access to resources based on predefined rules or policies. Authentication is the process of verifying the identity or legitimacy of a person or entity. A digital signature can authenticate the sender of a document, but it cannot authorize what actions the receiver can perform on the document.
Option C is incorrect because a digital signature does not dynamically validate modifications of data, but rather statically validates the integrity of data. A digital signature is based on a snapshot of the document at the time of signing, and any subsequent changes to the document will invalidate the digital signature. A digital signature does not monitor or update itself based on data modifications.
References:
CISA Online Review Course1, Module 5: Protection of Information Assets, Lesson 2: Encryption Basics, slide 13-14.
CISA Review Manual (Digital Version)2, Chapter 5: Protection of Information Assets, Section 5.2:
Encryption Basics, p. 273-274.
CISA Review Manual (Print Version), Chapter 5: Protection of Information Assets, Section 5.2: Encryption Basics, p. 273-274.
CISA Questions, Answers & Explanations Database3, Question ID: QAE_CISA_712.
What Is a Digital Signature (and How Does it Work)1
What are digital signatures and certificates?2
Digital Signature Definition3
Examples and uses of electronic signatures4
What is an Electronic Signature?5