【单选题】

Questions 1 to 5 are based on an interview.At the end of the interview you will be given 10 seconds to answer each of the following five questions. Now listen to the interview. People are likely to have a higher cholesterol level in winter because______.

A、they tend to take in less vitaminD、in that season
B、they do less exercise and become weaker than usual
C、they need to eat much more greasy food to keep warm
D、they get less sun to convert cholesterol into vitaminD