Which of the Following Functions Are Solutions to the Differential $\frac { d y } { d x } = - 25 y$

Multiple Choice

Which of the following functions are solutions to the differential equation $\frac { d y } { d x } = - 25 y$ ? (Mark all correct answers)

A) $y = \sin ( 5 x ) + \cos ( 5 x )$
B) $y = 5 \cos x - \sin x$
C) $y = e ^ { x / 5 }$
D) $y = e ^ { - x / 5 }$