instruction:
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: what is the greatest positive integer n such that 3 ^ n is a factor of 36 ^ 100 ?
Options: a. 100, b. 200, c. 300, d. 600, e. 900
answer:
b

question:
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
answer:
d

question:
Problem: susan made a block with small cubes of 5 cubic cm volume to make a block 7 small cubes long, 7 small cubes wide and 6 small cubes deep. she realise that she has used more small cubes than she really needed. she realised that she could have glued a fewer number of cubes together ot look like a block with same dimensions, if it were made
Options: ['a. 194', 'b. 195', 'c. 196', 'd. 197', 'e. 198']
answer:
a