Which of the Following Accurately Describes Vitamin D from the Sun

Which of the following accurately describes vitamin D from the sun? 

A)  Sunscreens with an SPF of 8 or higher increase vitamin D synthesis. 
B)  Only about one-half of the world's population relies on sunlight to maintain adequate vitamin D nutrition. 
C)  Prolonged exposure to sunlight degrades the vitamin D precursor in skin, thus preventing vitamin D toxicity. 
D)  For someone living in Chicago, vitamin D stores from the summer months are usually sufficient to meet the needs during the winter. 
E)  Pigments in dark skins increase vitamin D synthesis.