Which of the Following Defines an Exchange

Which of the following defines an exchange?

A) It is the mental and emotional processes of people who purchase and use goods and services to satisfy needs and wants.
B) It refers to exaggerated, subjective claims that cannot be proven true or false.
C) It refers to doing what society views as best for the welfare of people in general.
D) It is a process by which marketers search for unique groups of people whose needs can be addressed through specialized products.
E) It is a transaction in which one person or organization trades something of value with someone else.