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: in what time will a train 50 m long cross an electric pole, it its speed be 360 km / hr ?
Options: a. 0.25, b. 0.5, c. 1.5, d. 2.5, e. 3.5

Output: b


Input: Consider Input: Problem: 30 pens and 75 pencils were purchased for 750. if the average price of a pencil was 2.00, find the average price of a pen.
Options: a. 20, b. 11, c. 12, d. 13, e. 14

Output: a


Input: Consider Input: Problem: find the smallest number that should be multiplied with 54000 to make it a perfect cube.
Options: ['a. 4', 'b. 5', 'c. 6', 'd. 3', 'e. 7']


Output: a