Which one of the following statements is true for a simple harmonic oscillator?

A simple harmonic oscillator is defined by a restoring force that is directly proportional to the displacement from the equilibrium or mean position. According to Hooke's Law, expressed as F = -kx, this force always acts in the opposite direction to the displacement to bring the system back to equilibrium. Consequently, the acceleration is also proportional to the displacement and directed toward the center, meaning it is not constant but varies with position. The motion is periodic, and the velocity follows a sinusoidal function, making it periodic as well. Therefore, the only true statement is that the force is proportional to displacement and acts in the opposite direction.