Explanation:

- Option 1: Water will boil

- On the moon, there's no atmosphere to exert pressure on the liquid.

- Lower pressure decreases the boiling point drastically.

- Correct Answer

- Option 2: Water will freeze

- While the moon has cold surface temperatures, immediate exposure won’t lead to freezing due to initial boiling.

- Option 3: Nothing will happen to it

- With no atmospheric pressure, something will definitely happen.

- Option 4: It will decompose into H2 and O

- Decomposition requires energy input, like electrolysis or heat that isn’t present immediately.