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.

[EX Q]: 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
[EX A]: a

[EX Q]: Problem: a shopkeeper buys mangoes at the rate of 5 a rupee and sells them at 2 a rupee. find his net profit or loss percent ?
Options: a. 34 %, b. 30 %, c. 50 %, d. 150 %, e. 33 %
[EX A]: d

[EX Q]: Problem: 80 % of the population of a village is 64000. the total population of the village is ?
Options: a. 26799, b. 24000, c. 80000, d. 29973, e. 12312
[EX A]:
c