Some vitamins have overlapping roles in the body, while others have distinct roles. Match the vitamin with its primary or most well-understood function.
a) Vitamin b-6: part of a coenzyme needed for amino acid metabolism
b) Vitamin D: is a hormone
c) Vitamin E: is an antioxidant
d) Vitamin K: activates blood clotting factors
e) Niacin: Part of a coenzyme needed for energy metabolism"