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: 12. what is the dividend. divisor 17, the quotient is 9 and the remainder is 10.
Options: a. 150, b. 152, c. 154, d. 163, e. 144

Ex Output:
d

Ex Input:
Problem: a certain roller coaster has 6 cars, and a passenger is equally likely to ride in any 1 of the 6 cars each time that passenger rides the roller coaster. if a certain passenger is to ride the roller coaster 6 times, what is the probability that the passenger will ride in each of the 6 cars ?
Options: a. 3 / 1944, b. 1 / 96, c. 2 / 96, d. 1 / 1944, e. 1

Ex Output:
a

Ex Input:
Problem: when n is divided by 5 the remainder is 3. what is the remainder when ( n + 3 ) ^ 2 is divided by 5 ?
Options: a. 0, b. 1, c. 2, d. 3, e. 4

Ex Output:
b