To solve this problem, we need to identify which artificial sweetener is stable only under cold conditions.$\newline$Let's analyze each option:$\newline$• Option 1: Saccharine - This sweetener is stable under a wide range of conditions, including heat.$\newline$• Option 2: Sucralose - This sweetener is also stable under heat and is used in baking.$\newline$• Option 3: Aspartame - This sweetener is known to be unstable at high temperatures and is stable only under cold conditions.$\newline$• Option 4: Alitame - This sweetener is stable under various conditions, including heat.$\newline$Therefore, the artificial sweetener that is stable under cold conditions only is Aspartame.$\newline$This corresponds to Option 3.