Which of the following assumptions is embodied in the AFN equation?

a$.$ All balance sheet accounts are tied directly to sales.

b$.$ Common stock and long$-$term debt are tied directly to sales.

c$.$ Last year's total assets were not optimal for last year's sales.

d$.$ Fixed assets, but not current assets, are tied directly to sales.

e$.$ Accounts payable and accruals are tied directly to sales.