With ATMs, It Is Possible to Retrieve Cash from the Bank

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 difference has arisen because:

A) flexibility was not valued 100 years ago.
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) government forced banks to become more convenient.