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: in a certain deck of cards, each card has a positive integer written on it, in a multiplication game a child draws a card and multiplies the integer on the card with the next large integer. if the each possible product is between 10 and 400, then the least and greatest integer on the card would be
Options: a. 3 and 15, b. 3 and 20, c. 4 and 13, d. 4 and 14, e. 5 and 14

Ex Output:
b


Ex Input:
Problem: if julie rows 32 km upstream and 72 km down steam taking 4 hours each, then the speed of the stream
Options: a. 1.5 kmph, b. 0.5 kmph, c. 0.4 kmph, d. 1.6 kmph, e. 2.5 kmph

Ex Output:
b


Ex Input:
Problem: how long does a train 110 m long travelling at 60 kmph takes to cross a bridge of 200 m in length ?
Options: a. 18.6 sec, b. 14.9 sec, c. 12.4 sec, d. 16.8 sec, e. 11.8 sec

Ex Output:

a