Name a classic cocktail that features rum as its base spirit.

The choice of Daiquiri as a classic cocktail that features rum as its base spirit is spot on. The Daiquiri is a well-known cocktail that originated in Cuba, typically made from white rum, fresh lime juice, and sugar, shaken with ice and served in a chilled glass. Its simplicity and refreshing qualities have made it a timeless favorite among cocktail enthusiasts.

Each of the other options represents cocktails that utilize different base spirits. The Margarita primarily features tequila, known for its combination with lime juice and orange liqueur. The Martini, a classic, is centered around gin or vodka, often garnished with an olive or a lemon twist. The Old Fashioned is a traditional cocktail that generally highlights bourbon or rye whiskey, combined with sugar, bitters, and a twist of citrus peel. Understanding these distinctions is essential for recognizing the variety of flavors and styles found in classic cocktails, as well as the spirit choices that define them.