Among the given options (d) is the answer
A vibrating pendulum when it is just passing through its mean position is not the example of potential energy.
Potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.
When kinetic energy is maximum (at equilibrium position), potential energy is minimum at mean position. As the height from the base is 0, a vibrating pendulum at mean position is not an example of mean position.