Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C). Related Theory Vitamin B1 - Thiamine Vitamin B2− Riboflavin Vitamin B3− Niacin Vitamin B3 - Pantothenic acid Vitamin B6− Pyridoxine Vitamin B7− Biotin Vitamin B9 - Folic Acid vitamin B12− Cyanocobalomin