Why Do Artificial Sweeteners Have Less Calories Than Sucrose and Fructose

Why do artificial sweeteners have less calories than sucrose and fructose, but still taste sweet?

A) They bind to a specific taste receptor, but do not have any ATP.
B) They do not bind to any receptors and are quickly eliminated from the body.
C) They bind to ATP, which then binds to the taste receptor.
D) They bind to specific taste receptor, but are quickly metabolized by the body.