What is the most accurate rough order of magnitude (ROM)?

A.
In the Initiation phase, the estimate is in the range of +/- 50%.

B.
In the Planning phase, the estimate is in the range of +/- 50%.

C.
In the Monitoring and Controlling phase, the estimate is in the range of +/- 15%.

D.
In the Closing phase, the estimate is in the range of +/- 15%.