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 boat can travel with a speed of 25km/hr in still water. If the speed of the stream is 5km/hr, find the time taken by the boat to go 120km downstream.

 Option A: 1 hr

 Option B: 2 hrs

 Option C: 3 hrs

 Option D: 4 hrs

 Option E: 5 hrs
[EX A]: Option D

[EX Q]: Question: Find the greatest number which on dividing 1255 and 1490, leaves a reminder of 8 and 11 respectively

 Option A: 27

 Option B: 29

 Option C: 33

 Option D: 39

 Option E: 41
[EX A]: Option B

[EX Q]: Question: A man can row upstream at 8kmph and downstream at 13 kmph. The speed of the stream is

 Option A: 2.5 km/hr

 Option B: 4.2 km/hr

 Option C: 5 km/hr

 Option D: 10.5 km/hr

 Option E: None
[EX A]:
Option A