Which one of the following items is a direct cost?

Question $9$ options:

Utility costs of the administrative offices; the accounting department is the cost object.

Customer$-$service costs of a multiproduct firm; Product A is the cost object.

Printing costs incurred for payroll check processing; payroll check processing is the cost object.

The salary of a maintenance supervisor in a multiproduct manufacturing plant; Product B is the cost object.