A firm's value chain includes $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.$

Question $4$ options:

A$)$

primary activities that create value for customers.

B$)$

secondary activities that enhance the performance of primary activities.

C$)$

only internal activities.

D$)$

all the above.

E$)$

A and B only.