Final answer:
The time consumed during the swap out of a running process and swap in of a new process is known as the time taken for a context-switch, which is a significant overhead in multitasking systems.
Step-by-step explanation:
The correct answer to the student's question is option a) Context-switch. When a computer's operating system stops executing one process and begins executing another, the system performs a context switch.
This involves saving the state of the old process and loading the saved state of the new process to be executed. The time taken to perform a context switch is significant because it involves overhead for the CPU, which is not doing any productive work during this period. It is an essential part of a multiprogramming system where multiple processes share CPU time. However, excessive context switching can lead to a decline in system performance, often referred to as thrashing.