The excretory organs of different organisms are extremely varied. What do all excretory organs have in common?

A)a filtration system that results in a filtrate that is more concentrated than the body fluids
B)a filtration system that filters nitrogenous waste from the body fluids
C)a filtration system that relies on active transport to alter initial concentration of the filtrate
D)a filtration system that relies on extensive tubules with high ratio of surface area to volume to remove wastes