A person sitting in a running train, is an example of

The correct option is C

A body in state of rest as well as motion.

1. Since the train is running, which means the train is in motion.
2. The man is inside the train, so he is also in motion with respect to a person outside the train.
3. But man is in rest with respect to next person sitting his beside.
4. Hence, man is in a state of rest as well as motion.

Hence, option C is correct.