Which of the following items are expenses?

I. Paying for next accounting period's rent

II$.$ Buying inventory in cash

III. Paying unpaid wages, which relate to work completed in the previous accounting period

IV$.$ Purchasing a building in cash

V$.$ Paying off a bank loan

Select one:

a$.$ All of $I-V$ are expenses.

b$.$ None of I$-V$ are expenses.

c$.$ II and IV

d$.$ I, II$,$ IV

e$.$ III and V

f$.$ I, II$,$ III, IV