Final answer:
The saphenous vein is the correct answer as it is the only vein among the options listed that is located inferior to the trunk.
Step-by-step explanation:
The vein located inferior to the trunk among the options provided is the saphenous vein. The cephalic, axillary, and subclavian veins are all associated with regions above the trunk. The cephalic vein runs along the arm, the axillary vein in the armpit, and the subclavian vein beneath the collarbone. The saphenous vein, on the other hand, is the longest vein in the human body running along the length of the lower limb, thus being located inferior to the trunk.
The subclavian vein is located inferior to the trunk. It is deep in the thoracic cavity and becomes the axillary vein as it enters the axillary region. The subclavian vein drains the axillary and smaller local veins near the scapular region and leads to the brachiocephalic vein.