Using a continuous auditing module is an audit procedure that would provide the best assurance that an application program is functioning as designed. A continuous auditing module is a software tool that performs automated and continuous testing and monitoring of an application program's inputs, outputs, processes, and controls. A continuous auditing module can help to verify the accuracy, completeness, validity, reliability, and timeliness of the application program's data and transactions. A continuous auditing module can also help to identify and report any errors, anomalies, deviations, or exceptions in the application program's performance or compliance.
The other options are not as effective or relevant as using a continuous auditing module for providing assurance that an application program is functioning as designed. Interviewing business management is a technique for obtaining information and opinions from the users or owners of the application program, but it does not directly test or verify the functionality or quality of the application program. Confirming accounts is a technique for verifying the existence and accuracy of account balances or transactions, but it does not necessarily reflect the design or operation of the application program. Reviewing program documentation is a technique for examining the specifications, requirements, and procedures of the application program, but it does not provide evidence of the actual implementation or execution of the application program.
References:
* ISACA, CISA Review Manual, 27th Edition, 2019, p. 2361
* Continuous audit and monitoring - PwC2

The best recommendation to prevent unauthorized access to cloud-based applications and data is to implement multi-factor authentication (MFA). MFA is a method of verifying the identity of a user by requiring two or more pieces of evidence, such as a password, a code sent to a phone, or a biometric factor. MFA adds an extra layer of security to prevent unauthorized access, even if the user's password is compromised or stolen. MFA can also help comply with data privacy and security regulations, such as the General Data Protection Regulation (GDPR) and the Health Insurance Portability and Accountability Act (HIPAA).
The other options are not as effective as MFA in preventing unauthorized access. An intrusion detection system (IDS) is a tool that monitors network traffic and alerts administrators of suspicious or malicious activity, but it does not prevent access by itself. Updating security policies and procedures is a good practice, but it does not ensure that users follow them or that they are enforced. Utilizing strong anti-malware controls on all computing devices can help protect against malware infections, but it does not prevent users from accessing cloud-based applications and data from any Internet-connected web browser.
References:
ISACA, CISA Review Manual, 27th Edition, 2019, p. 2471
ISACA, CISAReview Questions, Answers and ExplanationsDatabase - 12 Month Subscription2 What Is Cloud Security? | Google Cloud3
5 Cloud Application Security Best Practices | Snyk4

The scanning will not degrade system performance. This is the most important consideration when establishing vulnerability scanning on critical IT infrastructure, because any degradation of system performance could affect the availability, reliability, and functionality of the IT services that depend on the infrastructure. Scanning during non-peak hours (A) could reduce the impact of scanning on system performance, but it does not guarantee that the scanning will not cause any degradation. Scanning followed by penetration testing (B) could provide more in-depth information about the vulnerabilities and their exploitability, but it does not address the potential impact of scanning on system performance. Scanning cost- effectiveness is a relevant factor for choosing a scanning service or tool, but it is not as important as ensuring that the scanning will not compromise the system performance.
Reference: CISA Vulnerability Scanning, Description.