A budget proposal is based on initial budget guidelines. Various factors have to be considered when putting the proposal together. Which statement lists an external factor that needs to be considered by a budget unit?

Group of answer choices

a$)$ Changes in the product design and mix

b$)$ Availability of raw materials and their prices

c$)$ Changes in the operating process of another budget unit that relies on this unit for supplies

d$)$ Adoption of new manufacturing processes