Question

consider the following force:
lucias hand is pushing on a door.
according to newtons third law, what other force must be happening?
the door is pushing on lucias hand.
the door is pulling on lucias hand.

Explanation:

Newton's third law states that for every action, there is an equal and opposite reaction. When Lucia's hand pushes on the door (action), the door must push back on Lucia's hand (reaction). A pull would not be the opposite reaction to a push. So the force that must be happening is the door pushing on Lucia's hand.

Answer:

The door is pushing on Lucia's hand.