Water table is lowered when ______ activity increases.
Water table is lowered when mining activity increases because the water table is an underground boundary between the soil surface and the area where groundwater saturates spaces between sediments and cracks in the rock. Water force and atmospheric force are equal at this boundary. Heavy rains or melting snow may reason the water table to rise, or heavy pumping of groundwater supplies may cause the water table to fall.
Thus, the correct option is A.