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.

[Q]: Question: Donald plans to invest x dollars in a savings account that pays interest at an annual rate of 8% compounded quarterly. Approximately what amount is the minimum that Donald will need to invest to earn over $100 in interest within 6 months?

 Option A: 1500

 Option B: 1750

 Option C: 2000

 Option D: 2500

 Option E: 3000
[A]: Option D


[Q]: Question: A man's speed with the current is 20 kmph and speed of the current is 3 kmph. The Man's speed against the current will be

 Option A: 11 kmph

 Option B: 12 kmph

 Option C: 14 kmph

 Option D: 17 kmph

 Option E: None of these
[A]: Option C


[Q]: Question: The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

 Option A: 12

 Option B: 15

 Option C: 14

 Option D: 18

 Option E: 19
[A]:
Option C