Which statement correctly defines clock speed in a CPU?

• A. The number of cores in a CPU
• B. The total processing time of a program
• C. The number of instructions a single processor core can carry out per second (Hz)
• D. The amount of cache per core

Answer: (C)

Clock speed is the rate at which the CPU’s clock ticks, measured in cycles per second (Hz). That ticking sets the pace for fetching, decoding, and executing instructions. A faster clock means more cycles occur each second, which generally allows more work to be done per second, although the exact instructions-per-second throughput also depends on the architecture and memory behavior. The statement that clock speed equals the number of instructions a core can carry out per second (in Hz) captures this per-second rate idea, which is why it’s considered correct here. The other options describe separate things—how many cores you have, the total elapsed time to run a program, or how much cache is available per core—not the clock’s speed.