Answer: Option A: The canoe would move backward a bit.
Explanation:
Newton's third law of motion states that for every action there is equal and opposite reaction. This means when you threw a heavy stone in front of you, you applied a force. Equal and opposite force acted on the canoe and it moved backward a bit.
Hence, according to Newton's third law of motion, when you throw a heavy stone forward, and equal amount of force will push the canoe backwards.