When a Customer Purchases an Item with a Debit Card

When a customer purchases an item with a debit card,

A) they actually are taking out a short-term loan with 30 days to pay before any interest is charged.
B) the payment flows first through an electronic clearinghouse which then sends the customer a bill.
C) the transaction duplicates the process of a credit card.
D) the funds are automatically transferred from the customer's account to the store's account.