A monitored mantrap at entrance and exit points would be the most effective compensating control in this scenario. A mantrap is a physical security access control system comprising a small space having two sets of interlocking doors such that the first set of doors must close before the second set opens. By implementing a monitored mantrap, unauthorized access can be prevented and it can ensure that all individuals are logged when they enter and exit the server room12.
References: ISACA's Information Systems Auditor Study Materials3

Comprehensive and Detailed Step-by-Step Explanation:
Theinternal audit team's roleinControl Self-Assessment (CSA)is toindependently validatemanagement's assessment to ensure accuracy and effectiveness.
Perform Testing to Validate Management's Assessment (Correct Answer - A) Ensures that self-assessments are reliable and comply with policies.
Example:Internal audit conducts sample tests to verify self-reported compliance.
Advising Management (Incorrect - B)
The audit teamreviewsrather than advises management.
Designing Testing Procedures (Incorrect - C)
Management should design CSA procedures, not auditors.
De-Scoping Business Processes (Incorrect - D)
Internal auditshould notreduce audit scope due to CSAs.
References:
ISACA CISA Review Manual
COBIT 2019: Control Self-Assessment

Allowing only corporate IM solutions is the best control to mitigate the malware risk associated with an IM system, because it can prevent unauthorized or malicious IM applications from accessing the network and infecting the system with malware. Corporate IM solutions can also enforce security policies and standards, such as encryption, authentication, and logging, to protect the IM system from malware attacks. Blocking attachments in IM, blocking external IM traffic, and encrypting IM traffic are also possible controls to mitigate the malware risk, but they are not as effective as allowing only corporate IM solutions. References: CISA Review Manual (Digital Version), Chapter 5, Section 5.4.4