Which of the following is NOT a part of a cocktail?

A cocktail is typically composed of several key components that work together to create a balanced and flavorful drink. The primary elements of a cocktail include the base, modifier, and mixer.

The base is the main alcoholic component, which forms the foundation of the drink. It's usually a spirit like vodka, gin, rum, whiskey, or tequila. The modifier refers to additional spirits or liqueurs that enhance or alter the flavor profile of the cocktail. Mixers are non-alcoholic ingredients, such as juices, sodas, or other beverages, that help dilute or complement the base and modifier.

Garnish, while important in the presentation and enhancement of a cocktail's aroma and visual appeal, is not considered a core part of the cocktail's composition. Instead, it serves to elevate the overall experience of the drink. Thus, the correct answer identifies garnish as the component that does not constitute a vital part of the cocktail itself.