On a critical project, with a short timeframe, a contractor found an omission in a proposal which had been submitted and approved. The contractor indicated this omission may change both scope and thus cost to the project. Upon receiving notification, the PM should ______.

A. submit, or ask the vender to submit, a change request to include the omission in the scope of the project
B. check the type of the contract used and approve the increase to the budget
C. since the project is falling behind, approve both the change in scope and the additional cost to the project to make sure the project is not delayed
D. gather more information