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.

Example Input: Problem: what is the greatest positive integer e such that 3 ^ e is a factor of 9 ^ 10 ?
Options: a. e = 5, b. e = 9, c. e = 10, d. e = 20, e. 30
Example Output: d

Example Input: Problem: a boat having a length 8 m and breadth 2 m is floating on a lake. the boat sinks by 1 cm when a man gets on it. the mass of the man is :
Options: a. 12 kg, b. 60 kg, c. 72 kg, d. 160 kg, e. none of these
Example Output: d

Example Input: Problem: a number is said to be prime saturated if the product of all the different positive prime factors of t is less than the square root of t. what is the greatest two digit prime saturated integer ?
Options: a. 99, b. 98, c. 97, d. 96, e. 95
Example Output:
d