单选题 Vitamins are another essential requirement for health. There are about forty known vitamins, but the most generally referred to are A, B, C, D and E. Deficiency of Vitamin A, found in carrots, rose -hips, liver, etc. , is alleged to affect the vision and the skin and reduce resistance to infection. Vitamin C, present in nearly all fruit, particularly oranges and other citrus fruit, has come to be regarded as particularly effective in the prevention of cold and low energy states.
What will probably happen to a person with Vitamin C deficiency according to the paragraph?

• A. He will be easily infected.
• B. He will have a poor vision.
• C. He will have smooth skin.
• D. He will catch cold ffequently.