If f(y)=y^2 and y is a positive integer, which of the following CANNOT be the value of f(f(y))? Choose the correct choice from the following answers:
A) 1	B) 144	C) 81	D) 16	E) 256
f(y)=y^2   f(f(y)) = (y^2)^2   =y^4   A. 1 , y=1   D. 16 , y=2   C. 81 , y=3   B. 144   f(y)=12   Square root of 12 is not a positive integer . Hence 144 can not be the value of f(f(y)) .   E. 256 , y=4   Answer 144
<result>B</result>
If f(y)=y^2 and y is a positive integer, which of the following CANNOT be the value of f(f(y))?