The correct answer is: C. Both A and B
A lien is a legal right to retain possession of property until a debt is paid. A lien can be created by law, by contract, or by operation of law.
In the case of goods that have not been sold on credit, the seller may have a lien on the goods to secure payment of the purchase price. This is known as a possessory lien. The seller can retain possession of the goods until the purchase price is paid, or until the buyer provides security for the debt.
In the case of goods that have been sold on credit, the seller may have a lien on the goods until the credit period expires. This is known as a contractual lien. The seller can retain possession of the goods until the credit period expires, or until the buyer pays for the goods.
Therefore, the seller can exercise a lien in both cases where goods have not been sold on credit and where goods have been sold on credit and the period of credit has expired.