According to the material seen in$$ class, which is the biggest contributor to the difference between US and European healthcare$$ costs?

A$.$

US healthcare quality is much higher

B$.$

US ability to get a$$ same$-$day appointment is much higher and$$ wait$-$times generally are much lower

C$.$

US returns to pharmaceutical innovations is much higher

D$.$

US cost of treatments in hospitals and in medical offices is much higher