The large connected urban area from boston to washington, dc, is often referred to as a(n)

This area is called Megalopolis, and more specifically the Northeast Megalopolis.

This includes Boston in the North of the Megalopolis, New York in the center and Washington in the south. It also includes Baltimore and Philadelphia.

About 50 Million people live there. 

The answer to this question is  c. pharmaceutical accumulation  reclaimed water refers to the water that being used again after it already  used for agricultural purposes.this type of water often contains pharmaceutical accumulation because of the chemical fertilizer that is used for the plants is absorbed into the water.