Which of the Following Statements Is True

Which of the following statements is true?

A) Since 1970,nutrition information has undergone few updates,because scientists have discovered all of the nutrients and determined their functions.
B) Dietary recommendations are generally based on the findings of one team of nutrition researchers.
C) The results of one study are usually enough to convince nutrition scientists to adopt new ideas about nutrition-related topics.
D) It is not unusual for similar studies,especially those involving human subjects,to have different findings.