Which Conditions Are Necessary for Marketing to Occur

Which conditions are necessary for marketing to occur?

A) a changing environment, a method of assessing needs, a way to communicate, and an exchange location
B) parties with cash or credit, a product, a reasonable price, and a place to make an exchange
C) a quality product, a fair price, a clever method of promotion, and a place where a customer can buy the product
D) two or more parties with unsatisfied needs, a desire and an ability to satisfy them, a way to communicate, and something to exchange
E) an ability to see a trend within an environmental force, a product, and an affordable and actionable advertising campaign