Select the Meaning of the Underlined Word in the Sentence

Select the meaning of the underlined word in the sentence.
The medical professionals highlighted that, if the hospital closed its doors, people in the area would have to travel over 100 miles to have access to tertiary health care.

A) the initial medical care given to an outpatient by a general health care provider
B) necessary treatment for a short period of time for a brief but serious illness, injury, or other health condition
C) advanced levels of medicine which are highly specialized and not widely accessed
D) specialized medical care given typically at a teaching hospital or research facility and usually preceded by referral from other physicians