Which of the following statement regarding concurrency is correct?

(A) In a single processor multiprogramming system, processes are interleaved in time to yield the appearance of simultaneous execution.

(B) The solution to the concurrency problem is to control access to the shared resources.

(C) In a uniprocessor system, the reason to cause the concurrency problem is that an interrupt can stop instruction execution anywhere in a process.

(D) In a multiprocessor system, one or more processors may be executing the same global variables at the same time.

(E) All of the above