Separating key responsibilities among multiple individuals is correct.

This option describes the separation of duties principle which ensures that critical steps in a process are split so that no single person can complete every stage of a sensitive transaction. By assigning initiation verification approval and execution to different people an organization reduces the risk of fraud error and misuse.

Restricting user permissions to specific resources is incorrect because that approach limits access but does not require different people to perform distinct parts of a transaction. Permissions are useful but they do not by themselves enforce a multiperson workflow.

Cloud IAM is incorrect because it names a category of tools for managing identities and access in cloud environments rather than the principle of dividing responsibilities among individuals. Cloud IAM can help implement separation of duties but it is not the concept the question is asking about.

Implementing defense in depth with multiple security layers is incorrect because that strategy focuses on layering technical and physical controls to reduce attack success rather than splitting tasks among staff. Layered defenses lower overall risk but they do not prevent one person from controlling every step of a sensitive transaction.

Full AWS Practitioner Certification Question