The name given to water when it is in a gaseous state is vapor.
The correct answer is "vapor." Water in its gaseous state is commonly referred to as water vapor. To arrive at this answer, you can recall your knowledge of the different states of water. Water can exist as a solid (ice), liquid (water), or gas (vapor) depending on its temperature. In this case, the question asks for the name of water in its gaseous state, which is water vapor.
