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: if the population of a certain country increases at the rate of one person every 15 seconds, by how many persons does the population increase in 25 minutes ?
Options: a. 80, b. 100, c. 150, d. 240, e. 300
[A]: b


[Q]: Problem: 1 men takes 37 $ to eat a pizza in restaurant such that it have discount multiple of 4 if u eat more pizza. discount increase by multiple of 4 every pizza u eat. for 1 pizza 0 % off. for 2 pizza % off for 3 pizza 8 % off. pizza without discount is 10 $. how much that man eats the pizza.
Options: a. 2, b. 3, c. 4, d. 5, e. 6
[A]: b


[Q]: Problem: a can do a piece of work in 15 days. a does the work for 5 days only and leaves the job. b does the remaining work in 18 days. in how many days b alone can do the work ?
Options: a. 5 days, b. 7 days, c. 27 days, d. 9 days, e. 10 days
[A]:
c