Which of the following statements is true of a value chain?

a$.$ The pre$-$ and postservice framework of a value chain emphasizes the notion that service is a critical component of traditional manufacturi

b$.$ The input$-$output framework of a value chain suggests that the value chain begins with inputs from customers.

c$.$ A value chain solely focuses on the operations function of an organization.

d$.$ A value chain is narrower in scope than a supply chain.