Zimmer-Centerpulse Is the World's Largest Producer of Replacement Hips and Knees

Zimmer-Centerpulse is the world's largest producer of replacement hips and knees for orthopedic surgery.They are particularly interested in marketing in the southwestern United States,where a large aging population lives.Which external environmental element most directly explains its continued growth?

A) Economic conditions
B) Political conditions
C) Culture
D) Demography
E) Social forces