Concept:A letter of inquiry is a buyer’s request for information about goods or prices.Explanation:When a buyer sends a letter of inquiry, the seller replies with a quotation.A quotation lists the prices, quantities, and terms for the requested products or services.Credit notes and debit notes are used to correct invoices or record returns.A delivery note is sent with goods when they are delivered.Therefore, the correct document sent in reply to an inquiry is a quotation.Answer:A. quotation