Good advice, except the RDA for Vitamin C is only sufficient to prevent scurvy, which is not the Optimum amount.
Optimum intakes should be between 2 to 4 grams or more to prevent heart disease and other maladies as defined by Dr M Rath and Linus Pauling. Apparently we lost our own ability to self-manufacture our own Vitamin C thousands of years ago. Most animals (except Guinea Pigs) produce their own Vit'C equivalent to an intake for humans of between 2 to 6 grams and even more if unwell.