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.

Input: Consider Input: Problem: 1391 x 1391 = ?
Options: a. a. 1951609, b. b. 1951601, c. c. 1951602, d. d. 1951603, e. e. 1934881

Output: e


Input: Consider Input: Problem: two trains of equal are running on parallel lines in the same direction at 45 km / hr and 36 km / hr. the faster train passes the slower train in 36 sec. the length of each train is ?
Options: a. 45, b. 88, c. 66, d. 55, e. 22

Output: a


Input: Consider Input: Problem: the ratio of number of boys and girls in a school is 3: 2. if there are 100 students in the school, find the number of girls in the school ?
Options: a. 25, b. 30, c. 35, d. 40, e. 50


Output: d