Final answer:
The short-term scheduler is the operating system component that selects which process in the ready queue should be executed next and allocates the CPU to that process. It is also known as the CPU scheduler and operates based on scheduling algorithms such as FCFS, SJF, or RR.
Step-by-step explanation:
The short-term scheduler, also known as the CPU scheduler, is a fundamental component of an operating system's process scheduling system. Its main role is to decide which process in the ready queue should be executed next by the CPU.
Answering the student's question, option b) It selects which process has to be executed next and allocates CPU is the correct choice. The short-term scheduler selects among the processes that are ready to execute and allocates the CPU to one of them. Its decision is typically based on a particular scheduling algorithm, like First-Come, First-Served (FCFS), Shortest Job First (SJF), or Round Robin (RR), among others.
The short-term scheduler operates very frequently and must be fast since it makes decisions for CPU allocation whenever a process switches from running to waiting state or vice versa, and especially when an interrupt occurs. Unlike the long-term or medium-term schedulers, the short-term scheduler does not deal with the swapping of processes into or out of the main memory.