Which ingredient is muddled in the Dirty Vegas cocktail?

In the Dirty Vegas cocktail, muddled strawberries are the key ingredient that contributes to its distinctive flavor profile. Muddling is the process of crushing fruit to release its juices and essential oils, which enhances the overall taste and aroma of the cocktail. The use of strawberries adds a sweet and fruity element that balances well with other ingredients, making the cocktail refreshing and enjoyable.

Other options do not relate to this specific cocktail. Lemons, for instance, are often used in various cocktails, but they are not a feature of the Dirty Vegas. Fresh mint, while a popular addition in many drinks, is not muddled in this particular recipe, and guavas are typically found in tropical cocktails rather than this one. Thus, the choice of muddled strawberries is not only correct, but it's also integral to achieving the signature characteristics of the Dirty Vegas cocktail.