Which of the following statement is true about the U.S. health care delivery system? Group of answer choices a)It follows neither the highly regulated single-payer model nor a free market model b)Prices charged for health care services remain less than the true economic costs of production c)Since it follows the highly regulated single-payer model, utilization remains largely checked d)Costs incurred in health research and development (R&D) are excluded from total health care expenditures