Given the question: Write a multi-choice question for the following article, with the given choices and answer: Article: The vitamins are named by letters of the alphabet . Vitamin A is needed by the eyes. There is Vitamin A in milk, butter, and green vegetables. It can be kept by the body. Vitamin B cannot be kept. It must be supplied all the time by some of the food we eat. Vitamin C is very important to the body. Without it men's teeth become loose and their arms and legs get weak. Lemons , oranges and tomatoes have Vitamin C in them. Vitamin D is the sun vitamin. We get it in milk and eggs and from sunlight on our skin . There are other Vitamins, but these A, B, C and D, are the most important. Options: A we have bread and butter for our breakfast B we are eating fruits C we are working in the field in the sun D we are having eggs Answer: C we are working in the field in the sun Question:
The answer is:
We can get Vitamin D when _ .