what is the best vitamin d supplement on the market?
['Nordic Naturals Vitamin D3 at Amazon. "Provides 1,000 IU in a small capsule form."', 'NatureWise at Amazon. ... ', 'Caltrate at Amazon. ... ', 'Solgar at Amazon. ... ', 'Megafood at Amazon. ... ', 'Nature Made Vitamin D3 at Amazon. ... ', 'Country Life Vitamin D3 at Amazon.']