Question 2 (1 points): An alternative to the multi-level feedback queue style of designs for approximating SRTF is to try to record the length of CPU bursts, and use the average of recent CPU burst times to make a scheduling decisions. In order to perform the task of a recording the length of CPU bursts, an operating system can time how long a process runs each time it is scheduled. This will result in a sequence of timings, one for each time the thread is scheduled on a core. The length of each CPU burst (suitable for approximating SRTF) is equal to A. O the length of exactly one of the timings B. O the sum of these timings, starting from some point when the thread was preempted and going until it next was preempted C. O the sum of these timings, starting from some point when the thread was preempted and going until it next ceased to be runnable D. O the sum of these timings, starting from some point when the thread became runnable and going until it next ceased to be runnable E. O the sum of these timings, starting from some point when the thread become runnable and going until it is next preempted