The correct response that demonstrates Newton’s third law is:
When the octopus ejects the water out, the water acts with an equal force on the octopus in the opposite direction.
This illustrates Newton's third law, which states that for every action, there is an equal and opposite reaction. When the octopus pushes the water out of its funnel (action), the water pushes back against the octopus with an equal force in the opposite direction (reaction), propelling the octopus forward.