Final answer:
The best quantum time for the given scenario, with process runtimes less than 10ms, is a. 15ms since it closely matches the process runtime, ensuring efficiency and reduced response times in a Round-Robin scheduling method.
Step-by-step explanation:
The subject question regarding quantum time (tQ) for a Round-Robin timesharing method in context with processes having a short runtime (less than 10ms) asks which quantum time value would result in the smallest response times. Considering the means by which CPU time is allocated in a Round-Robin scheduling algorithm, the quantum time should be of a magnitude comparable to the process runtimes to ensure efficiency and minimal overhead.
A quantum time that is too long could result in longer waits for processes, as each process would hold the CPU for the entire quantum even if it requires much less time to complete. Therefore, a quantum time of 15ms (option a), closest to the process runtime and shorter than the other provided options, would typically be ideal for minimizing response times in this scenario.