Which cocktail features bourbon as its primary ingredient?

The Old Fashioned is a classic cocktail that prominently features bourbon as its primary ingredient. This cocktail traditionally combines bourbon with a sugar cube, a few dashes of bitters, and a twist of citrus peel, typically orange. The focus on bourbon gives the Old Fashioned a rich and robust flavor profile, highlighting the complexity of the whiskey.

Bourbon, being a type of American whiskey made primarily from corn, lends notable sweetness and depth to this drink, making it a favorite among bourbon enthusiasts. The simplicity of the ingredients allows the flavor of the bourbon to shine through, making it a quintessential representation of bourbon-based cocktails.

In contrast, the other choices focus on different spirits as their primary base. The Martini is primarily made with gin or vodka, the Margarita centers around tequila, and the Mojito features rum, which establishes their distinction from the Old Fashioned.