Which one of the following equation at the repressents simple harmonic motion ?

Which one of the following equations of motion represents simple harmonic motion?

Which one of the following equations of motion represents simple harmonic motion ?

Which one of the following equations of motion represents simple harmonic motion ?

Which one of the following equations of motion represent simple harmonic motion?

Which one of the following equations of motion represents simple harmonic motion ?

Which one of the following equations of motion represent simple harmonic motion? Where k, k_(0), k_(1) and a are positive.

In a simple harmonic motion