To make​ on-campus financial transactions​ easier, a university issues cards with embedded microchips to students. The cards are loaded with an amount of money and they can then be used to make purchases a variety of places on​ campus, such as the​ bookstore, the​ cafeteria, parking​ meters, and even vending machines. This is an example of​ a(n) _______.
A. Electronic funds transfer (EFT)
B. Debit card
C. Automated clearing house (ACH) network
D. Smart card
E. Letter of credit