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.
Q: Problem: 5 people can write 25 book in 20 days working 8 hour a day. then in how many day 125 can be written by 75 people ?
Options: a. 25 / 3, b. 19 / 3, c. 20 / 3, d. 25 / 3, e. 22 / 3
A:
c