Approximately how many cubic feet of water are needed to fill a circular swimming pool that is 80 feet across and 10 feet deep? Choose the correct choice from the following choices:  A) 10000  B) 50000  C) 80000  D) 85000  E) 90000

Rationale: "answer should be b . v = \ pir ^ 2 h = \ pi * 40 ^ 2 * 10 = approximately 50000"
Answer: B