3.1) A quotation is a written form response to an enquiry, telling the enquirer the price and other terms of transaction. In this sense, the term “_____” is often used as “quotation” in international trade, today. However, in practice, _____ is usually a “_____”.            
 
A、offer, a quotation, firm offer  
B、quotation, an offer, quotation
C、quote, an offer, firm offer  
D、offer, an offer, firm offer