Final answer:
The two major lymphatic vessels are the Right lymphatic duct, which drains the upper right side of the body, into the right subclavian vein, and the Thoracic duct, which drains lymph from the majority of the body into the left subclavian vein. The correct option is A.
Step-by-step explanation:
The two major vessels formed after the uniting of large lymphatic trunks in a person’s lymphatic system are the Right lymphatic duct and the Thoracic duct.
The right lymphatic duct drains lymph fluid from the right side of the head, thorax, and right upper limb into the right subclavian vein.
In contrast, the thoracic duct, which begins at the cisterna chyli, drains lymph from the rest of the body — including the lower abdomen, pelvis, and lower limbs — into the left subclavian vein.