Which ingredient is not included in the "Pineapple Cucumber Mule" combination?

The "Pineapple Cucumber Mule" is a refreshing cocktail that typically features a blend of ingredients designed to complement the primary flavors of pineapple and cucumber. Ginger is often included as it adds a spicy kick that enhances the overall flavor profile, while pineapple serves as the main fruit component, providing sweetness and tropical notes. Alfalfa, although less common, can be used for garnish or as a unique twist, but it wouldn’t detract from the essence of the drink.

Lemonade is not a standard ingredient for this cocktail. While it could potentially provide a citrus element, the classic "Pineapple Cucumber Mule" focuses on the specific combination of ginger, pineapple, and cucumber. This places lemonade outside the expected ingredients of this cocktail, making it the correct answer.