You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: One water pump can fill half of a certain empty tank in 7 hours. Another pump can fill half of the same tank in 7.5 hours. Working together, how long will it take these two pumps to fill the entire tank?

Option A: 7 7/13

Option B: 1 5/8

Option C: 3 1/4

Option D: 7 7/29

Option E: 3 1/2
Option D

Question: The radius of a wheel is 22.4 cm. What is the distance covered by the wheel in making 1500 resolutions?

Option A: 2112 m

Option B: 2704 m

Option C: 2278 m

Option D: 2288 m

Option E: 2378 m
Option A

Question: What is the remainder if 7^4 is divided by 100?

Option A: 5

Option B: 4

Option C: 1

Option D: 2

Option E: 10
Option C