Which choice below is an example of a perfectly closed system?

Question

An automoblie moving down the highway .energy transfer only occurs inside the motor
A cup of water with ice in it, open to the air.
A cup of tea with a lid on it. energy transfer takes place with the cup and the surroundings, but no matter leaves the tea.
Newton's cradle. The energy transfer only occurs between the balls.

Answer 1

Newton's cradle. The energy transfer only occurs between the balls.