Revolving credit is open.
Most credit cards are unsecured.
The answer should be OPEN AND UNSECURED
A person using an unsecured credit card is not spending his own money right away whenever he uses the credit card. Instead, he is borrowing money from his/her bank; more like he/she takes out a loan whenever the card is used, which he is expected to pay back so as to maintain a trustworthy credit history.