Heather is absolutely exhausted. She has been working at the hospital until 3 a.m. and delivered three babies. She goes home for a quick shower only to go back to the hospital since there are three more moms waiting to deliver their babies. What kind of doctor is Heather?

a
cytotechnologist

b
phlebotomist

c
anesthesiologist

d
obstetrician

d. obstetrician