Which of the following is a common type of mixer used in cocktail preparation?

Soda is a common type of mixer used in cocktail preparation because it enhances the drink by adding fizziness and sweetness, making it more refreshing. It can be used with a variety of spirits to create cocktails like a rum and Coke, whiskey and soda, or vodka soda, among others.

In contrast, bourbon and whiskey are spirits themselves, primarily serving as the base for cocktails rather than mixers. Red wine, while also used in some cocktails, does not typically act as a mixer in the same way that soda does. Instead, it is often enjoyed on its own or in specific wine-based cocktails but does not provide the same versatility as soda in a wide range of mixed drinks.