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 walking at a constant rate of 4 kilometers per hour is passed by a cyclist travelling in the same direction along the same path at a constant rate of 24 kilometers per hour. the cyclist stops and waits for the hiker 5 minutes after passing her while the hiker continues to walk at her constant rate. how many minutes must the cyclist wait until the hiker catches up ?
Options: a. 10, b. 15, c. 20, d. 25, e. 30
[EX A]: d

[EX Q]: Problem: a man spends 2 / 5 of his salary on house rent, 3 / 10 of his salary on food and 1 / 8 of his salary on convenience he has rs. 1400 left with him, find his expenditure on food and conveyance.
Options: a. 1000, b. 3000, c. 4000, d. 2000, e. 5000
[EX A]: a

[EX Q]: Problem: the ratio of number of boys and girls in a school is 2: 5. if there are 350 students in the school, find the number of girls in the school ?
Options: a. 150, b. 250, c. 300, d. 370, e. 280
[EX A]:
b