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.
--------
Question: Problem: how many prime numbers are between 76 / 8 and 124 / 5 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5

Answer: e


Question: Problem: the mean proportional between 4 and 16 is ?
Options: a. 12, b. 13, c. 14, d. 15, e. 16

Answer: e


Question: Problem: there is a 5 - digit number. the fifth digit is one fourth of the third digit and one half of the fourth digit. third digit is one half of the first digit. second digit is 5 more than the fifth digit. what is that 5 - digit number ?
Options: a. 86421, b. 86424, c. 89421, d. 96421, e. 76421

Answer:
a