Which of the Following Is a Characteristic of Niacin Nutrition

Which of the following is a characteristic of niacin nutrition?

A) In foods,it is more unstable than thiamin and riboflavin
B) The average intake is slightly lower than the RDA in the United States
C) The amount in a serving of whole-wheat bread is about twice that in a serving of peanut butter
D) About half of the daily need for most people could be met by the tryptophan found in protein foods