The correct answer is 3. This method of recording depicts a patient who begins at 15° of flexion and ends at 90° of elbow flexion.
0-15-90 is not acceptable, as there are two distinct values to the right of the zero
15-0-90 indicates the patient has 15° of elbow hyperextension
0-90 depicts a patient who can fully extend the elbow and flex the elbow to 90°