Which Transaction Best Describes Bartering

Which transaction best describes bartering?

A) an exchange of goods for currency, in which the price of something is determined by establishing its value against an underlying commodity
B) a transfer of goods without an exchange of currency, in which the price of something is determined by the seller, and the buyer agrees to pay him at a later time
C) an exchange of goods without an exchange of currency, in which the price of something is determined by the needs and resources of each person involved in the exchange
D) an exchange of goods for currency, in which the price of something is determined by what buyers are willing to pay