Water vapor in the earth's air is an example of a solution. what type of solution would this be

Water vapor in the earth's air is an example of a liquid in a gas solution.

The solution is a homogeneous mixture of two or more ingredients with one ingredient in a large excess (solvent). Substances that are not at their disposal are dissolved substances or solutes. Dissolved molecules are isolated from each other due to the vast majority of the solvent molecules so that the solvent dictates the properties of the dissolved substances in the solution.

Common examples are a kitchen salt or sugar dissolved in water. Also, gases can also be dissolved in liquids, e.g. carbon dioxide and oxygen in the water.

In our case, the air is in a larger amount than the water vapor, so it is a solvent.  

The correct answer is d