The prime lending rate of commercial banks is an announced rate and is often understated from the viewpoint of even the most credit-worthy firms. Which one of the following requirements always results in a higher effective interest rate?

A floating rate for the loan period.
A covenant that restricts the issuance of any new unsecured bonds during the existence of the loan.
The imposition of a compensating balance with an absolute minimum that cannot be met by current transaction balances.
The absence of a charge for any unused portion in the line of credit.