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: Find the sum lend at C.I. at 5 p.c per annum will amount to Rs.441 in 2 years?

 Option A: Rs.900

 Option B: Rs.800

 Option C: Rs.500

 Option D: Rs. 400

 Option E: Rs.200
[A]: Option D


[Q]: Question: If j and k are integers whose product is 400, which of the following statements must be true?

 Option A: n + k > 0

 Option B: n is not equal to k.

 Option C: Either n or k is a multiple of 10.

 Option D: If n is even, then k is odd.

 Option E: If j is odd, then k is even.
[A]: Option E


[Q]: Question: What is the product of all the prime factors of 21?

 Option A: 20

 Option B: 21

 Option C: 18

 Option D: 17

 Option E: 16
[A]:
Option B