The answer is 1, either ( AA, Aa, or aa ) .
The most appropriate unit for describing a 26 mile marathon run would be C. Kilometre. As kilometres can be easily utilized and converted to miles and vice-versa.
When prolonged and excessive rainfall the more water percolates and the water table (below the earth surface/soil) rises. The higher the water table the more the possibility increases for a spring to form in the sense that it would now be easier for the water to find a means of escaping the underground through perhaps a crack or a cave, etc.
