Please choose the correct answer to the question: When a transverse wave passes from right to left through a medium, what happens to the particles of the medium?

Answer1: Particles travel from right to left along the wave. Answer2: Particles travel from left to right along the wave. Answer3: Particles move back and forth parallel to the wave. Answer4: Particles move back and forth perpendicular to the wave.

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