$f : R \to R$, defined by $f(x)=\sin x$ and $g : R \to R$, defined by $g(x) = x^2, \; (fog) (x)$ is equal to :

Question

( A ) $\sin^2x$
( B ) $x^2 + \sin x$
( C ) $\sin x^2$
( D ) $x^2 \sin x$