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.

Ex Input:
Problem: a train covers a distance of 100 km in 1 hour. if its speed is decreased by 15 km / hr, the time taken by the car to cover the same distance will be ?
Options: a. 1 hr, b. 1 hr 10 min, c. 50 min, d. 1 hr 30 min, e. 1 hr 45 min

Ex Output:
b


Ex Input:
Problem: if p ( a. = 5 / 7 and p ( b. = 2 / 5, find p ( a n b. if a and b are independent events.
Options: a. 7 / 25, b. 3 / 25, c. 8 / 25, d. 2 / 7, e. 3 / 17

Ex Output:
d


Ex Input:
Problem: the average weight of a, b and c is 60 kg. if the average weight of a and b be 70 kg and that of b and c be 50 kg, then the weight of b is :
Options: a. 50 kg, b. 60 kg, c. 55 kg, d. 57 kg, e. 62 kg

Ex Output:

b