As a result of improved technology, many medical and surgical procedures can be done on an outpatient basis, which means that the patient does not have to

...be admitted at the health facility.

Outpatient is defined by a patient who receives medical treatment without being admitted to a hospital.

Inpatient is defined by a patient who stays in a hospital while under treatment.

For Example: Let's take cancer patient's for instance, they are able to receive treatment by just going in for their appointment and then returning home afterwards. (Outpatient) Oppose to being admitted into the hospital and staying there, sleeping there, as well as receiving their treatment etc. (Inpatient)

d would be your answer