In the Following Equations,a Is Acceleration,r Is a Fixed Distance,s $\pi$

Multiple Choice

In the following equations,a is acceleration,r is a fixed distance,s is displacement,and m is mass.Which equation describes simple harmonic motion?

A) a = -kr²
B) a = $\pi$ r²
C) a = -ks^-1
D) a = 4 $\pi$ mr²/3
E) a = - 4 $\pi$ ms/3