Which of the following statements does not explain why US health care expenditures are higher than in other countries?
选项：

A:Government policies have shifted the health care production function downward over time.
B:Consumer incomes have increased, which allows consumers to purchase more health care.
C:The US health care system is relatively inefficient compared to other countries.
D:Demand for health care in the US has increased, so health care production occurs at a higher point on the total product curve than in other countries.