* The feature in collaboration software that allows only one user to modify a document at a time ensures data integrity.
* Data integrity refers to the accuracy and consistency of data over its lifecycle.
* By restricting modification access to one user at a time, the system prevents concurrent changes that could lead to data conflicts or corruption.
* The other options:
* Data availability ensures data is accessible when needed.
* Data confidentiality ensures data is protected from unauthorized access.
* Data accessibility refers to the ease of accessing data.
* Therefore, ensuring data integrity is the purpose of this feature.
References:
* "Database Systems: The Complete Book" by Hector Garcia-Molina, Jeffrey D. Ullman, and Jennifer Widom, which discusses data integrity.
* "Collaborative Computing: Theory, Practice, and Tools" by Vladimir Dimitrov, which covers features in collaboration software.

The correct answer is B - Parallel simulation test.
WGU Cybersecurity Architecture and Engineering (KFO1 / D488) defines a parallel simulation test as simulating a disaster recovery process where systems are restored at an alternate site without actually taking the primary systems offline. It allows organizations to test full restoration capabilities while avoiding disruption of live operations.
Walk-throughs (A) and tabletop exercises (D) are lower-impact simulations. Full interruption tests (C) would stop operations, which the company wants to avoid.
Reference Extract from Study Guide:
"Parallel simulation tests validate the ability to recover and operate critical systems at an alternate site without affecting primary business operations."
- WGU Cybersecurity Architecture and Engineering (KFO1 / D488), Disaster Recovery Testing Types

* Proprietary softwareis a type of software that is owned by an individual or a company.
* It is usually sold commercially and comes with acommercial software license.
* This type of license typically restricts the ways in which the software can be used, modified, and distributed.
* Users must agree to the terms of the license, which often include restrictions on copying, sharing, and modifying the software.
* Example:Microsoft Windows and Adobe Photoshop are proprietary software products.
References:
* "The Cathedral and the Bazaar" by Eric S. Raymond.
* "Understanding Open Source and Free Software Licensing" by Andrew M. St. Laurent.

The correct answer is B - Asymmetric encryption.
According to WGU Cybersecurity Architecture and Engineering (KFO1 / D488), asymmetric encryption uses a pair of public and private keys, allowing the sender to encrypt the documents with the recipient's public key, ensuring that only the recipient's private key can decrypt them. This guarantees confidentiality even over an unsecured network.
Stream ciphers (A) and block ciphers (C) are types of symmetric encryption, requiring a shared secret key.
Hash functions (D) provide integrity, not confidentiality.
Reference Extract from Study Guide:
"Asymmetric encryption enables secure data exchange by allowing encryption with a public key and decryption only with a corresponding private key, ensuring confidentiality over unsecured networks."
- WGU Cybersecurity Architecture and Engineering (KFO1 / D488), Cryptographic Methods and Key Management

Application Software:
Application software refers to programs that help end users perform specific tasks. Examples include email clients, word processors, and spreadsheet programs.
These are designed to be used by people to perform tasks such as writing documents, managing data, or communicating.
Operating Systems:
Operating systems (OS) manage the hardware and software resources of a computer system. They provide a platform for application software to run.
Examples include Microsoft Windows, macOS, and Linux. The OS handles system-level tasks like memory management, process scheduling, and hardware interaction.
Key Differences:
Application software (B, C) is user-oriented, aimed at helping users complete tasks.
Operating systems (A, D) manage the computer's hardware and system resources.
References:
Application software: Application Software
Operating system functions: Operating System Functions