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: The average of first ten prime numbers which are odd is?

 Option A: 15.5

 Option B: 15.7

 Option C: 15.2

 Option D: 15.8

 Option E: 15.1
[EX A]: Option D

[EX Q]: Question: In a certain school, the ratio of boys to girls is 5 to 13. If there are 160 more girls than boys, how many boys are there?

 Option A: 100

 Option B: 36

 Option C: 45

 Option D: 72

 Option E: 117
[EX A]: Option A

[EX Q]: Question: If f(y)=y^2 and y is a positive integer, which of the following CANNOT be the value of f(f(y))?

 Option A: 1

 Option B: 144

 Option C: 81

 Option D: 16

 Option E: 256
[EX A]:
Option B