The Nephron of Mammals and Malpighian Tubules of Insects Are

The nephron of mammals and Malpighian tubules of insects are both involved in water and salt balance. They are also similar in that they are both

A) involved in elimination of nitrogenous wastes.
B) involved in the elimination of digestive wastes.
C) attached to the digestive system.
D) attached to the respiratory system.
E) found in the kidneys.