For how many integers n 2^n = n^2

a none
b one
c two
d three
e more than 3

[spoiler]
ANS C[/spoiler]

acc to me its B i.e one

when n =2,
2^n = n^2
2^2 = 2 ^2

it can not be zero

2^0 = 0^2
1 = not defined

pls point out my mistake