Who should contribute to the development of the project plan?

Thank you for invitation. Option D. Entire project team including project manager is good answer.

Correct Answer is D. Whole team has to contribue, however Project Manager is accountable and responsible for all.

Thank you for the invitation

Thanks for the information 

I Agree Option D

Of course it is option D but P M is accountable for the entire project which includes planning as well.

D. Entire project team including project manager

Project Manager and Planning Department

Thanks for the invitation. My answer is D