With ATMs, it is possible to retrieve cash from the bank at any time. One hundred years ago, one could only get cash from the bank during business hours, say, 9 am to 3 pm. The present availability of 24-hour service has arisen because:

With ATMs, it is possible to retrieve cash from the bank at any time. One hundred years ago, one could only get cash from the bank during business hours, say, 9 am to 3 pm. The present availability of 24-hour service has arisen because:
A.government forced banks to become more convenient.
B.it was impossible to provide 24-hour service 100 years ago.
C.the cost of providing 24-hour service is much lower today.
D.flexibility was not valued 100 years ago.
正确答案：the cost of providing 24-hour service is much lower today.