Which of the Following Best Explains Why a Single 24-Hour

Which of the following best explains why a single 24-hour recall is unsuitable for characterizing usual dietary intake?

A) Subjects may withhold information about what they eat due to embarrassment.
B) Subjects may forget what they ate.
C) Food and nutrient intake varies so much from day-to-day.
D) Subjects often change their usual diet in order to simplify the act of recording.