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: if a and b are the roots of the equation x 2 - 9 x + 9 = 0, then the value of a 2 + b 2 is :
Options: a. 63, b. 24, c. 17, d. 6, e. 5

Output: a


Input: Consider Input: Problem: a student travels from his house to school at 10 km / hr and reaches school 2 hours late. the next day he travels 18 km / hr and reaches school 1 hour early. what is the distance between his house and the school ?
Options: a. 65.0, b. 67.5, c. 70.0, d. 72.5, e. 75.0

Output: b


Input: Consider Input: Problem: 2 persons can finish a job in 8 days. first person alone can finish the work in 24 days. how many days does the second person take to finish the job ?
Options: a. 10 days, b. 12 days, c. 14 days, d. 16 days, e. 18 days


Output: b