The correct answer is portal vein.
The hepato portal vein carries carbohydrates and other essential nutrients from the spleen and gastrointestinal track to the liver. The length of this vein is three to four inches and is usually formed by merging of splenic and superior mesentric vein. The blood which is carried by the portal vein is then processed and the toxic elements are removed from it and the useful part are sent back to the bloodstream.
