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.

[EX Q]: Question: A man performs 3/5 of the total journey by rail, 17/20 by bus and the remaining 6.5 km on foot. His total journey is :

Option A: 125 km

Option B: 130 km

Option C: 135 km

Option D: 140 km

Option E: None
[EX A]: Option B

[EX Q]: Question: Three number are in the ratio 5:6:7. The sum of its largest and smallest numbers equals the sum of the third number and 48. Find the third number?

Option A: 87

Option B: 57

Option C: 48

Option D: 26

Option E: 28
[EX A]: Option C

[EX Q]: Question: The population of locusts in a certain swarm doubles every two hours. If 4 hours ago there were 1,000 locusts in the swarm, in approximately how many hours will the swarm population exceed 32,000 locusts?

Option A: 2

Option B: 4

Option C: 6

Option D: 8

Option E: 9
[EX A]:
Option C