The correct answer is: A. Conventional Memory
Conventional memory is the first 640 kilobytes (KB) of a PC’s memory. It is used by the operating system and other essential programs. Upper memory blocks (UMBs) are a type of memory that can be used by programs that do not fit in conventional memory. They are located in the first 1 megabyte (MB) of memory, above the 640 KB limit of conventional memory.
Extended memory is the memory that is above 1 MB. It is not directly accessible by the CPU, but it can be used by programs through the use of a memory
manager such as EMM386.Expanded memory is a type of memory that is used to
expand conventional memory. It is not directly accessible by the CPU, but it can be used by programs through the use of a memory manager such as QEMM.Reserved memory is memory that is reserved for use by the operating system and other essential programs. It is not available for use by other programs.
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