The program manager is asking why your project is scheduled to take sixteen months. He claims that previous projects in the organization were able to be completed in less than half of that time. What would be the BEST thing to do?

A.  Look for historical information on the previous projects to understand them better.
B.  Refer the program manager to the schedule management plan.
C.  Refer the program manager to the project plan .
D.  Explain to the program manager that estimates should always err on the side of being too large.