Concept:A closed indent is an international trade order that restricts the agent to buy from a specific supplier.
Explanation:In foreign trade, an indent is an order sent by an importer to an agent for purchasing goods.
A closed indent names a particular supplier and instructs the agent to buy only from that supplier.
An open indent allows the agent to choose the supplier on the importer's behalf.
A letter of credit is a bank guarantee ensuring payment to the seller.
A letter of enquiry is only a formal request for information about goods.
Therefore, the document that instructs buying from a particular supplier is the closed indent.
Answer:D. closed indent