What is a value chain?

What is a value chain?
A . It includes inbound logistics, operations, outbound logistics, marketing and sales, service, firm infrastructure, human resources management, and technology.
B . It creates value to the market by considering demographic, technological, economic, and political factors.
C . It is a chain of actions that measure the increasing value of an economic good being manufactured.
D . It describes the performance of a set of company shares. Common examples of value chains are Dow Jones and DAX.

Answer: A