The correct answer is: A. rain excess of 30%.
An index of wetness is a measure of how wet a place is. It is calculated by taking the average annual rainfall and dividing it by the average annual potential evapotranspiration. Potential evapotranspiration is the amount of water that would evaporate from a surface if there was no water shortage.
A 70% index of wetness means that the average annual rainfall is 70% of the average annual potential evapotranspiration. This means that the place is receiving more rain than it needs. The excess rain will either run off or soak into the ground. If it runs off, it can cause flooding. If it soaks into the ground, it can cause waterlogging.
Option B is incorrect because it says that a 70% index of wetness means that the place is receiving 30% less rain than it needs. This is not the case. The place is receiving 30% more rain than it needs.
Option C is incorrect because it says that a 70% index of wetness means that the place is receiving 70% less rain than it needs. This is not the case. The place is receiving 30% more rain than it needs.
Option D is incorrect because it says that none of the above is the correct answer. However, A is the correct answer.