What is the primary difference between logical clocks and time-of-day clocks in a distributed system? A. Logical clocks do not measure time of the day, only relative ordering of events, whereas time-of-day clocks measure absolute time B. Logical clocks measure elapsed time, whereas time-of-day clocks measure relative ordering of events C. Logical clocks are synchronized with NTP, whereas time-of-day clocks are not D. Logical clocks have a fixed confidence interval, whereas time-of-day clocks have variable confidence intervals