The correct answer is C - Control.
According to WGU Cybersecurity Architecture and Engineering (KFO1 / D488), the control phase of the risk management life cycle involves implementing appropriate security measures or countermeasures to mitigate or eliminate identified risks. After a risk is assessed, controls are applied to address it and reduce its impact or likelihood.
Assess (A) evaluates risk severity. Identify (B) discovers risks. Review (D) checks the effectiveness of applied controls.
Reference Extract from Study Guide:
"The control phase of risk management focuses on applying security controls and mitigations to reduce the risk to an acceptable level."
- WGU Cybersecurity Architecture and Engineering (KFO1 / D488), Risk Management Life Cycle