The correct response is:
The object would fall down from one side of the hole to the edge of the other side, and then fall back down to the start. This pattern would continue forever.
This is because Earth's gravity pulls objects towards its center, so if you were to drop an object into a hole through the Earth, it would be pulled towards the center of the Earth and then fall back down to the starting point. The force of gravity would cause this pattern to continue indefinitely.