The motion that is repeated at regular intervals is termed as –
A) Vibration
B) Ventilation
C) Oscillation
D) Periodic Motion

Hint: We have to understand the various forms of the motion around us and differences in defining them at different instances according to a general behaviour of each motion. We can compare each of the motions given in the different options.

Complete answer:
We know that any object undergoing a change in position with respect to time relative to its surrounding is said to be in motion. We have defined various types of motions executed by the objects in various constraints.
The motion along a straight line or rectilinear motion, motion along a circular path or circular motion are some of the main types of motion. We can compare each of the given motions to understand which of them is repeated after a regular interval.
1.Vibration: It is the displacement of the particle from a mean position back-and-forth with a high frequency. It is a motion associated with particles rather than larger bodies. It is generally a periodic motion, a motion which repeats regularly, when a particle is displaced from its equilibrium condition by external force. The vibration is a restoring motion. But they can be irregular too.
2.Ventilation: It is the breathing motion which is repeated regularly but not at constant intervals.
3.Oscillation: It is a motion about a mean position which repeats. The oscillations can be either periodic or non-periodic depending on various factors.
4.Periodic motion: The motion that repeats itself regularly after equal intervals of time is called the periodic motion.

The correct answer is option D.

Note:
The vibrations, oscillations and ventilations can be periodic motions if they strictly repeat after a regular interval of time. These motions can be tampered by external factors or other damping conditions which can resist them from maintaining the time period.