Consider an arbitrary set of CPU-bound processes with unequal CPU burst lengths submitted at the same time to a computer system. Which one of the following process scheduling algorithms would minimize the average waiting time in the ready queue?

Shortest Remaining Time First (SRTF), or Shortest Job First (SJF) when all processes arrive at the same time ($t = 0$), is provably optimal in terms of minimizing the average waiting time for a given set of processes.

• (A) Shortest remaining time first reduces the average waiting time because shorter processes execute first, thereby not delaying subsequent shorter jobs by large execution times.

• (B) Round-robin introduces extra context-switching overhead and generally has a higher average waiting time than SJF/SRTF.

• (C) Uniform random does not prioritize shorter bursts and yields sub-optimal average waiting time.

• (D) Priority proportional to burst length behaves like Longest Job First (LJF), which actually maximizes the average waiting time.

Therefore, option A is the correct answer.