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: the price of a certain painting increased by 30 % during the first year and decreased by 15 % during the second year. the price of the painting at the end of the 2 - year period was what percent of the original price ?
Options: a. 102 %, b. 105 %, c. 110.5 %, d. 112.5 %, e. 100 %
Example Output: c

Example Input: Problem: a hiker walked for 3 days. she walked 18 miles on the first day, walking 3 miles per hour. on the second day she walked for one less hour but she walked one mile per hour, faster than on the first day. on the third day 5 miles per hour for 6 hours. how many miles in total did she walk ?
Options: a. 68, b. 44, c. 58, d. 60, e. 62
Example Output: a

Example Input: Problem: in township k, 1 / 5 of the housing units are equipped with cable television. if 1 / 10 of the housing units, including 1 / 3 of those that are equipped with cable television, are equipped with videocassette recorders, what fraction of the housing units have neither cable television nor videocassette recorders ?
Options: a. 23 / 30, b. 11 / 15, c. 7 / 10, d. 1 / 6, e. 2 / 15
Example Output:
a