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: 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
[A]: Option B


[Q]: Question: A reduction of 20% in the price of salt enables a lady to obtain 10kgs more for Rs.100, find the original price per kg?

 Option A: Rs.3.2

 Option B: Rs.2.9

 Option C: Rs.2.5

 Option D: Rs.5.2

 Option E: Rs.2.1
[A]: Option C


[Q]: Question: The breadth of a rectangular field is 60% of its length. If the perimeter of the field is 800 m, find out the area of the field.

 Option A: 37500

 Option B: 38000

 Option C: 38500

 Option D: 39000

 Option E: 39500
[A]:
Option A