The answer should be B. According to the conservation of energy, the energy cannot be created nor destroyed, but it can be transformed. Since the object is moving down, that means its height is decreasing, causing the potential energy decreasing and the kinetic energy increasing to fulfill the conservation law.
The period of a pendulum is given by

where L is the pendulum length and g is the gravitational acceleration.
We can write down the ratio between the period of the pendulum on the Moon and on Earth by using this formula, and we find:

where the labels m and e refer to "Moon" and "Earth".
Since the gravitational acceleration on Earth is

while on the Moon is

, the ratio between the period on the Moon and on Earth is
A system that repeats to and from its mean or rest point. that executes harmonic motion. a few examples I've heard of are since the springtime a mass-spring system,a swing, simple pendulum, one more example is a steel ball rolling in a curved is this what you need or do you need three more sentences dish. to get S.H.M a body just displaced away from the resting position and of course then is released. the human body oscillates due to the reinforce that pulls it back do you need anything else answered on this and I'll answer it
It's momentum is twice as much.