How Has the Widespread Adoption of Debit Cards as the Preferred

How has the widespread adoption of debit cards as the preferred method of payment for consumer purchases likely affected bank administration costs?

A) the cost of bank administration is unaffected by widespread use of debit cards
B) costs increased due to high cost of developing and maintaining debit card technology
C) administration costs increased because the cost of electricity means high-cost for electronic transactions
D) costs are reduced because the cost of purchase is immediately debited from purchaser's checking account