Introduction:
Virtual memory is a memory management technique that allows a computer to compensate for the limited physical memory by using a combination of hardware and software to temporarily transfer data between primary memory (RAM) and secondary storage (hard disk). It provides the illusion of a larger memory space than the physical memory available.

Explanation:
Let's analyze each statement to determine which one is false:

a) Virtual memory implements the translation of a program's address space into physical memory address space:
This statement is true. Virtual memory uses a technique called address translation to map a program's virtual address space into physical memory. Each program is given a separate virtual address space, which is divided into fixed-size pages. These pages are mapped to physical memory frames using a page table, allowing programs to access memory locations that may not be contiguous in physical memory.

b) Virtual memory allows each program to exceed the size of the primary memory:
This statement is true. Virtual memory allows each program to exceed the size of the primary memory by using secondary storage as an extension of physical memory. When a program requires more memory than is available in physical memory, the operating system transfers less frequently used portions of the program's address space to secondary storage, freeing up physical memory for other programs or data. This allows programs to run even if their total memory requirements exceed the available physical memory.

c) Virtual memory increases the degree of multiprogramming:
This statement is true. Virtual memory increases the degree of multiprogramming, which refers to the ability of a computer system to execute multiple programs simultaneously. By allowing programs to use more memory than is physically available, virtual memory allows for better utilization of system resources and enables the system to run more programs concurrently. This increases the degree of multiprogramming and improves overall system performance.

d) Virtual memory reduces the context switching overhead:
This statement is false. Virtual memory does not reduce the context switching overhead. Context switching refers to the process of saving the state of a running program and restoring the state of another program for execution. Virtual memory itself does not directly impact the context switching overhead. Context switching is necessary regardless of whether virtual memory is used or not, as it is a fundamental operation in multitasking operating systems.

Conclusion:
The false statement is option 'D'. Virtual memory does not reduce the context switching overhead. It is important to understand the concepts and benefits of virtual memory in computer systems to optimize performance and manage memory effectively.