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 car is 15 minutes late by running at a speed of 4 / 5 th of its actual speed. the actual time taken by the car to cover that distance is :
Options: a. 30 minutes, b. 1 hour, c. 2 hours, d. 3 hours, e. none of these
b

Problem: four bells commence tolling together and toll at intervals of 2, 4, 6, 8 seconds respectively. in 18 minutes, how many times do they toll together ?
Options: a. 43, b. 44, c. 45, d. 46, e. 47
c

Problem: the cost of the paint is rs. 40.00 per kg. if 1 kg of paint covers 20 sq. ft, how much will it cost to paint outside of a cube having 10 feet each side
Options: a. rs. 1200, b. rs. 672, c. rs. 546, d. rs. 876, e. none of these

a