Find the Second Derivative of the Function $f(x)=5 e^{x} \cos x$

Multiple Choice

Find the second derivative of the function. $f(x) =5 e^{x} \cos x$

A) $10 e^{x} \sin x$
B) $10 e^{x} \cos x$
C) $-10 e^{x} \cos x$
D) $-10 e^{x} \sin x$