The correct answer is option 1: Aorta. The aorta is the largest blood vessel in the human body and is part of the circulatory system. It is responsible for carrying oxygenated blood from the heart to various parts of the body. The aorta originates from the left ventricle of the heart and extends downwards, eventually branching out into smaller blood vessels to supply blood to all organs and tissues.
Option 2, Anatomises, is not a blood vessel and is not correct.
Option 3, Tunica Intima, is a layer of the blood vessel wall and not the blood vessel itself, so it is not the largest blood vessel.
Option 4, Atrium, refers to one of the chambers of the heart and is not a blood vessel, so it is not the largest blood vessel.
Therefore, the correct answer is option 1: Aorta.