Please choose the correct answer to the question: The metal lid on a glass jar is hard to open, so it is held under warm, running water. What causes the jar to open easily after it was held under the water?

Answer1: The water increased the pressure under the lid. Answer2: The jar shrunk with the warm water. Answer3: The water acted as a lubricant between the glass and the metal. Answer4: The metal lid expanded under warm water.

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