Final answer:
The subclavian trunks receive lymph from the upper limbs. They then drain into the right and left subclavian veins through the right lymphatic duct and the thoracic duct, respectively.
Therefore, option a is correct.
Step-by-step explanation:
The lymph from the upper limbs is received by the subclavian trunks. The superficial and deep lymphatics of the upper limbs merge to form these larger lymphatic vessels which then drain into the subclavian veins, specifically the right lymphatic duct draining into the right subclavian vein for the right upper limb, and the thoracic duct into the left subclavian vein for the left upper limb. It's important to note that the thoracic duct is the main collector for most of the body's lymph, except for the upper right quadrant which is served by the right lymphatic duct, but it is the subclavian trunks that specifically gather lymph from the upper limbs.