Which action can a developer take to enforce this requirement?

exams DEX-450 DEX-450 exam 0 Comments

A reviewer is required to enter a reason in the comments field only when a candidate is recommended to be hired.

Which action can a developer take to enforce this requirement?
A . Create a required Visualforce component.
B . Create a formula field.
C . Create a required comments field.
D . Create a validation rule.

Answer: D