Which modification indicates that whipped cream should be added?

The abbreviation that indicates whipped cream should be added is WC. This stands for "whipped cream," making it a clear and direct reference for baristas when preparing drinks. When an order includes this modification, it signals that whipped cream should be a part of the final presentation, enhancing the drink's texture and flavor.

In contrast, other modifications serve different purposes. For example, SOY typically refers to soy milk, indicating a dairy alternative in the beverage. WCM, which could represent white chocolate mocha, is related to a specific flavor or recipe rather than a topping. MP could denote a modification regarding milk or foam, but does not specify adding whipped cream. Thus, WC is the most precise choice for indicating that whipped cream is to be included.