The water increased the pressure under the lid. The jar shrunk with the warm water. The water acted as a lubricant between the glass and the metal. The metal lid expanded under warm water.
I am hesitating between 4 options to answer the following question, which option should I choose?
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?
Possibilities:
- The water increased the pressure under the lid.
- The jar shrunk with the warm water.
- The water acted as a lubricant between the glass and the metal.
- The metal lid expanded under warm water.

The metal lid expanded under warm water.