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: the area of a square field is 625 km 2. how long will it take for a horse to run around at the speed of 25 km / h ?
Options: a. 12 h, b. 10 h, c. 8 h, d. 4 h, e. none of these

Output: d


Input: Consider Input: Problem: the sum of the ages of 5 children born at the intervals of 3 year each is 60 year. what is the age of the youngest child ?
Options: a. 4 year, b. 6 year, c. 10 year, d. none of these, e. 9 year

Output: b


Input: Consider Input: Problem: a clock shows the time as 7 a. m. if the minute hand gains 5 minutes every hour, how many minutes will the clock gain by 6 p. m. ?
Options: a. 45 minutes, b. 55 minutes, c. 35 minutes, d. 25 minutes, e. 40 minutes


Output: b