The asymmetric information problem in the market for healthcare services is​ _______.

a. some people cannot afford private healthcare insurance
b. people know when they have a healthy lifestyle
c. hospitals prefer to treat patients with serious health needs because this maximizes hospital profit
d. medical workers have private information about a patient's condition, the treatments available, and the cost-effectiveness of the treatment they prescribe.
e. that the healthiest people choose to be insured