What modification would indicate that a customer wants to remove an ingredient?

The indication that a customer wants to remove an ingredient is typically represented by a minus symbol. This convention is widely recognized in many food and beverage contexts where customers specify modifications to their orders.

By using the minus symbol, it clearly communicates to the staff that the customer does not want a particular ingredient included in their beverage. This is particularly important for special dietary needs or personal preferences, ensuring that the order is prepared according to the customer's specifications.

In contrast, the other symbols mentioned do not commonly represent the removal of ingredients; for instance, the plus symbol often signifies the addition of an ingredient, while the other symbols have alternative meanings or are not standard in this context. Therefore, the minus symbol effectively conveys the intention to omit something, making it the correct choice for this question.