How can artificial sweeteners taste like sugar but not actually be sugar?

a. artificial sweeteners anesthetize normal tongue receptors so signals of sweetness are sent to the brain instead of what the "sweetener" really tastes like.

b. artificial sweeteners are absorbed directly into the bloodstream, bypassing the tongue, and causing your hypothalamus to think you have eaten something sweet.

c. artificial sweeteners stimulate the same taste buds that sugar does because they have a chemical structure that closely resembles that of sugar.

d. artificial sweeteners stimulate a different part of the tongue than sugar does, fooling it into thinking you have sugar in your mouth.

e. none of the above is true?