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: A sum of Rs.4800 is invested at a compound interest for three years, the rate of interest being 10% p.a., 20% p.a. and 25% p.a. for the 1st, 2nd and the 3rd years respectively. Find the interest received at the end of the three years?

 Option A: Rs.3129

 Option B: Rs.3120

 Option C: Rs.3108

 Option D: Rs.3106

 Option E: Rs.3127
[A]: Option B


[Q]: Question: The average weight of 10 person's increases by 4 kg when a new person comes in place of one of them weighing 70kg. What is the weight of the new person?

 Option A: 85

 Option B: 86.5

 Option C: 90

 Option D: 88.5

 Option E: 110
[A]: Option E


[Q]: Question: If x is an odd negative integer and y is an even integer, which of the following statements must be true? I. (3x + 2y) is positive integer II. xy^2 is positive integer III. (y^2 - x) is positive integer

 Option A: I,II only

 Option B: I only

 Option C: II only

 Option D: III only

 Option E: none of these
[A]:
Option D