Please choose the correct answer to the question: When you are riding a bicycle at night, your bicycle's reflectors help people in cars see your bicycle. How do bicycle reflectors work?

Answer1: They are made of a special material that gives off its own light. Answer2: They are hooked up to batteries that allow them to produce light. Answer3: They bounce light back from other sources. Answer4: They are covered with paint that glows in the dark.

Answer format: answer1/answer2/answer3/answer4