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 100 meters long completely crosses a 300 meters long bridge in 36 seconds. what is the speed of the train is ?
Options: a. 32 kmph, b. 76 kmph, c. 34 kmph, d. 43 kmph, e. 40 kmph

Ex Output:
e


Ex Input:
Problem: what is the tens digit of 6 ^ 10 ?
Options: a. 7, b. 3, c. 5, d. 1, e. 9

Ex Output:
a


Ex Input:
Problem: two trains of length 180 m and 280 m are running towards each other on parallel lines at 42 kmph and 30 kmph respectively. in what time will they be clear of each other from the moment they meet ?
Options: a. 22 sec, b. 23 sec, c. 76 sec, d. 20 sec, e. 66 sec

Ex Output:

b