Find the Derivative Of $f ( x ) = \sin ^ { 2 } x + 3 \cos ^ { 2 } x$

Multiple Choice

Find the derivative of $f ( x ) = \sin ^ { 2 } x + 3 \cos ^ { 2 } x$

A) $2 \sin x + 6 \cos x$
B) $2 \sin 2 x$
C) $4 \sin 2 x$
D) $- 2 \sin 2 x$