On Monday, Sylvester walked up 50 stairs in 1 minute. On Tuesday, Sylvester walked up 100 stairs in 2 minutes. Which best describes Sylvester's work and power? a. He did equal work and used equal power on both days. b. He did equal work both days, but used more power on Tuesday. c. He did more work on Tuesday, and used more power on Tuesday. d. He did more work on Tuesday, but used equal power on both days.