Please choose the correct answer to the question: Otto pushed a toy car across a floor. The car traveled fast across the wood, but it slowed to a stop on the carpet. Which best explains what happened when the car reached the carpet?

Answer1: Inertia decreased. Answer2: Gravity increased. Answer3: Friction increased. Answer4: Magnetism decreased.

Answer format: answer1/answer2/answer3/answer4
Answer: answer3