Which modification suggests adding a topping of nutmeg?

The choice indicating a nutmeg sprinkle is relevant as it directly points to the specific topping in question. When someone suggests adding nutmeg as a topping, it implies that a sprinkle of nutmeg would enhance the flavor profile of the beverage, providing a warm, aromatic note that complements various coffee drinks. Nutmeg is often associated with comfort beverages and can elevate the overall sensory experience of a drink.

The other options, while they may enhance beverages in different ways, do not pertain specifically to nutmeg. A mocha base refers to a chocolate-infused coffee base, whipped cream is a common topping that adds creaminess and sweetness, and Splenda is a type of sweetener. None of these directly suggest nutmeg, thereby highlighting why a nutmeg sprinkle is the most appropriate choice for this modification.