Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
--------
Question: Problem: a train 510 m long is running at a speed of 45 km / hr. in what time will it pass a bridge 140 m long ?
Options: a. 40, b. 52, c. 26, d. 21, e. 14

Answer: b


Question: Problem: an error 1 % in excess is made while measuring the side of a square. the percentage of error in the calculated area of the square is :
Options: a. 2.01, b. 30.1, c. 3.01, d. 25.01, e. 4.05

Answer: a


Question: Problem: out of 250 students of a college, 160 play football, 90 play cricket and 50 neither play football nor cricket. how many students play both football and cricket ?
Options: a. 30, b. 40, c. 50, d. 60, e. 70

Answer:
c