The LeVitre and Swezey Credit Union maintains separate bank accounts for each of its 20,000 customers. Three major files are the customer master file, the transaction file of deposits and withdrawal information, and a monthly statement file that shows a customer's transaction history for the previous month. The following lists the bank's most important activities during a representative month:

a. Customers make deposits and withdrawals.

b. Employers make automatic deposits on behalf of selected employees.

c. The bank updates its master file daily using the transaction file.

d. The bank creates monthly statements for its customers, using both the customer master file and the transactions file.

e. Bank personal answer customer questions concerning their deposits, withdrawals, or account balances.

f. The bank issues checks to pay its rent, utility bills, payroll, and phone bill.

Draw a data flow diagram that graphically describes these activities.