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.
When an object is dropped into a hole that goes straight through the Earth, it would initially accelerate towards the center due to gravity. As it reaches the center, the gravitational force would decrease and become zero at the center, causing the object to continue moving outward toward the opposite side. When it reaches the opposite edge, it would start to fall back down toward the center again. This oscillation would continue indefinitely, assuming there is no air resistance or friction to slow it down.