Which artificial sweetener contains chlorine?

We begin by recalling the molecular compositions of the four commonly discussed artificial sweeteners mentioned in the question.

Sucralose is a chlorinated derivative of sucrose. Three of the hydroxyl groups present in the parent sugar $$C_{12}H_{22}O_{11}$$ are replaced by chlorine atoms, giving the empirical formula $$C_{12}H_{19}Cl_3O_8$$. Because of these three chlorine atoms, sucralose is sometimes described as a “trichloro-sucrose” compound.

Alitame is a dipeptide-based sweetener. Its structure contains carbon, hydrogen, nitrogen, and oxygen in addition to a small amount of sulfur, but it has no chlorine atoms anywhere in its molecule.

Saccharin is an o-sulfobenzamide with the formula $$C_7H_5NO_3S$$. This molecule provides intense sweetness but again has no chlorine atoms.

Aspartame, another dipeptide-based sweetener, has the formula $$C_{14}H_{18}N_2O_5$$ and likewise contains no chlorine atoms.

From these observations we see that only sucralose explicitly incorporates chlorine in its chemical structure, whereas alitame, saccharin, and aspartame do not contain any chlorine.

Hence, the correct answer is Option A.