What must be included in every drink that contains cherry syrup?

A drink that contains cherry syrup must include a stemmed cherry to enhance its presentation and align with traditional garnishing practices. The use of a stemmed cherry not only adds visual appeal to the drink but also emphasizes the cherry flavor, making it a recognizable feature that complements the syrup's sweetness. This garnish is often expected in cocktails and beverages that feature cherry ingredients, providing a cohesive and enjoyable experience for those consuming the drink.

In contrast, the other options do not serve the same specific purpose of complementing or highlighting the cherry syrup and can vary widely based on the type of drink being prepared. While lemon wedges, mint sprigs, or lime slices can contribute to other cocktails, they do not inherently relate to cherry syrup in the same way a cherry garnish does.