A master's level swimmer reads that taking Vit C supplements can help prevent respiratory infections during heavy training. He has a history of getting sick during intense training periods each year, so he decides to try supplementation. His diet is high in fruits and vegetables, he takes tow 500mg Vit C tablets three times daily, and drinks Vit C fortified immunity drinks. According to the National Academy of Sciences DRI report, what is the tolerable upper intake level (UL) for Vitamin C?
a. 500mg
b. 5000mg
c. 1500mg
d. 2000mg
