Final answer:
Planning unit personnel must be able to accept feedback and revise their plans.
Step-by-step explanation:
The correct answer is A. feedback.
Planning unit personnel must be able to accept feedback and, where appropriate revise their plans. Accepting feedback is important as it allows for improvement and growth. Feedback can come from various sources such as managers, peers, or readers, and it provides valuable insights and suggestions that can help in making revisions and improving plans.