Show that the motion of a spring-mass system is simple harmonic motion and derive the equation for the frequency of oscillations of the system.

A) Hooke's law explains the relationship between force and displacement in a spring-mass system.
B) The motion of a spring-mass system is periodic and can be described by a sinusoidal function.
C) The frequency of oscillations (f) of a spring-mass system is given by f= 1/2π √(k/m) , where k is the spring constant and m is the mass.
D) All of the above.