The correct answer is D. Virtual memory.
The 80286 processor supports virtual memory, which allows multiple programs to run simultaneously by using a technique called paging. Paging divides the physical memory into fixed-size pages, and each program is assigned a set of pages. When a program needs to access a page that is not currently in physical memory, the operating system swaps the page in from disk. This allows the 80286 to run multiple programs even if they have more memory than is physically available.
Real mode is a mode of operation for the 80286 processor that is compatible with the 8086 processor. In real mode, the 80286 processor can only access 1MB of memory. Address access is the ability of a processor to access memory addresses. Data access is the ability of a processor to read and write data from memory.