What additional ingredient is included in a strawberry shake besides white milk?

The inclusion of 2 oz. of strawberry topping in a strawberry shake is essential because it provides the signature flavor that defines the beverage. The strawberry topping not only enhances the overall taste by offering a fruity sweetness but also contributes to the shake's rich, creamy texture. This ingredient is specifically designed to complement the white milk and other components of the shake, ensuring that the flavor profile is consistent with what customers expect when ordering a strawberry shake.

In contrast, the other ingredients listed do not align with the traditional recipe for a strawberry shake. Chocolate syrup would give the shake a completely different flavor, vanilla is typically used as an ice cream base rather than an additional ingredient in a fruit flavor shake, and cheesecake would alter both the taste and texture significantly. Thus, the correct choice emphasizes the importance of the strawberry topping in achieving the intended flavor experience.