(2%) When designing an embedded I/O data acquisition path, engineers often choose between an interrupt-driven approach and polling. Which statement is correct?
A Under high event rates, an interrupt-driven design is always more power efficient than polling because the CPU does not repeatedly read a status register, and interrupts do not introduce meaningful context-switch overhead.
B In periodic polling, the average detection latency is mainly determined by the polling period. If event arrivals are uniformly distributed within each polling interval, the expected detection latency is approximately half the polling period, while the worst-case detection latency can be bounded by roughly one polling period (ignoring the polling routine's execution time).
C Using edge-triggered interrupts eliminates interrupt storms, so edge-triggered interrupts are always preferable to level-triggered interrupts for high-frequency events, and no additional debouncing or throttling mechanisms are necessary.
D With polling, increasing the polling frequency simultaneously reduces latency and CPU utilization because the system can detect events sooner and return to sleep earlier; therefore high-frequency polling is typically better for power.
