A student solved this problem and said the answer was hour 3/4. Cindy rode her bike for 1/2 hour and ran for 1/4 hour. What was the total length of time that Cindy exercised? Is the student's answer reasonable?
A. Yes, the answer is reasonable.
B. No, the answer is not reasonable. It should be about 2 hours.
C. No, the answer is not reasonable. It should be about 1/4 hour.
D. No, the answer is not reasonable. It should be about 6 hours.