The correct option is Ensure that staff conducting the authorization understand the system boundaries.

Defining the information system scope establishes what is inside and outside the authorization boundary and it tells assessors which assets, services, and interfaces must be evaluated. When the team Ensure that staff conducting the authorization understand the system boundaries they can identify applicable controls, determine inherited controls from the cloud provider, plan assessment activities, and allocate resources correctly.

Cloud Identity and Access Management is a control domain or capability and not the reason to define scope. It may be important to evaluate identity and access controls after scoping but it does not replace defining the authorization boundary.

Confirm that all security controls are implemented across every component is incorrect because confirmation of control implementation comes after the scope and control selection are defined. The team must first know which components are in scope before they can verify implementation or apply tailored controls.

Ensure that every security related risk is fully mitigated is incorrect because authorizations accept some level of residual risk. The authorization process aims to ensure risks are understood and are reduced to an acceptable level but it does not guarantee that every single risk is fully mitigated.

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