If the air temperature increased, with no addition or removal of water vapour, the actual vapour pressure would:

The correct answer is A. Increase.

The actual vapor pressure is the pressure exerted by the water vapor in the air. The saturation vapor pressure is the maximum amount of water vapor that the air can hold at a given temperature. When the air temperature increases, the molecules of water vapor move faster and have more energy. This allows them to escape from the surface of the water and enter the air. As more water vapor enters the air, the actual vapor pressure increases.

Option B is incorrect because the actual vapor pressure will increase, not decrease, as the air temperature increases. Option C is incorrect