Q: 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.
Problem: a person x started at 3 hours earlier at 40 km / h from a place p, then another person y followed him at 60 km / h. started his journey at 3 o ' clock, afternoon. what is the diference in time when x was 30 km ahead of y and when y was 30 km ahead of x ?
Options: a. 8 h, b. 3 h, c. 6 h, d. 3 h, e. 1 h
A:
b