The Anti-diuretic Hormone helps to control blood pressure by acting on the kidneys and the blood vessels. Its most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in the urine. And so in times of dehydration it could help your body save more water. I think the statement is correct.
If i'm not mistaken, it's the aorta
I think the answer is A! i might be wrong