A group of physicians conducts a study to find the success rate of different treatments for an illness. They select one hospital

A group of physicians conducts a study to find the success
rate of different treatments for an illness. They select one
hospital at random and obtain a list of patients who have
received each treatment. They select every fifth patient on
the list and contact that patient.
What is the sample in this study?
A. Patients who have been diagnosed with the illness
B. The patients from the list who are contacted by the physicians
C. Patients who received one of the treatments at the selected
hospital
D. The patients on the list that the hospital provided to the doctors