The correct answer is B. MEM.
MEM is a command-line utility that displays information about the amount of physical and virtual memory available on a computer. It can also be used to configure memory usage.
EMM is a memory manager that was used in MS-DOS to expand the amount of memory available to applications. It is no longer necessary in modern operating systems.
CHKDSK is a command-line utility that checks the integrity of a disk and fixes any errors that it finds. It does not display information about memory usage.
MEMMAKER is a memory configuration utility that was used in MS-DOS to optimize memory usage. It is no longer necessary in modern operating systems.
None of the above is the correct answer.