Pfizer divested its consumer businesses in 2019, and its off-patent and generic businesses in 2020. The company then focused on the development and production of patent-protected pharmaceuticals sold by prescription.

a. Explain why the demand for prescription drugs depends on physicians and insurance companies.

b. Compare the advertising elasticity of demand of consumers vis--vis physicians and insurance companies.

c. Compare the price elasticity of demand for off-patent vis--vis patented drugs.

d. Explain why, between 2018 and 2020, Pfizer cut expenditure on advertising from 6.6% to 5.8% to 4.3% of revenue.