Final answer:
The rubor of dependency test is a diagnostic method used to detect C) arterial insufficiency by observing color changes in an extremity when it is positioned below the heart level.
Step-by-step explanation:
The rubor of dependency test is used to assess the presence of C) arterial insufficiency.
This diagnostic procedure involves elevating the patient's leg and then watching for color changes as the leg returns to a dependent (below the level of the heart) position.
In the presence of arterial insufficiency, the affected extremity will show a ruddy discoloration, known as rubor, upon dependency due to the dilation of blood vessels as part of the body's effort to increase blood supply in compensation for the reduced arterial flow.