A section of code that may only be executed by one process at any one time is

CPM
Critical resource
Critical region
Gray code E. None of the above

The correct answer is C. Critical region.

A critical region is a section of code that may only be executed by one process at any one time. This is to ensure that the data in the critical region is not corrupted.

A critical resource is a resource that is shared by multiple processes. This resource must be managed carefully to ensure that it is not accessed by multiple processes at the same time.

CPM is a project management technique. It stands for Critical Path Method.

Gray code is a type of code that is used to represent numbers. It is a non-repeating code.

None of the above is a section of code that may only be executed by one process at any one time.