If f(x)=cos(2x)f(x) = \cos(2x)f(x)=cos(2x), find f(4)(x)f^{(4)}(x)f(4)(x) (the fourth derivative).
16cos(2x)16 \cos(2x)16cos(2x)
−16cos(2x)-16 \cos(2x)−16cos(2x)
8cos(2x)8 \cos(2x)8cos(2x)
4cos(2x)4 \cos(2x)4cos(2x)