Answer:
C. the patient's joints
Step-by-step explanation:
Osteoarthritis is a type of arthritis that is most common and affects millions of people all around the world. Aging is one of the most common causes of Osteoarthritis. In Osteoarthritis the cartilage between the bonds deteriorates and two bones rub on each other which causes joint inflammation.
So as from the medical record, it can be seen that the patient has been diagnosed with OA therefore the patient's joints were most likely examined before making this diagnosis. So the right answer is C.