A large adult cardiology practice decides to hire a new MD and place them in one of their existing clinics to provide better access for patients in the market. Before the new MD was hired, the clinic saw an average of 24 patients per day. They plan for the new MD to see an average of 12 patients per day, 4 of which are existing patients of the practice. How many incremental patients will the new MD add to the cardiology practice per day?

A-24

B-12

C-20

D-8