单选题 Which of the following nutritional deficiencies may delay wound healing?
A. Lack of thiamine.
B. Lack of vitamin Ｃ.
C. Lack of folate.
D. Lack of vitamin Ａ.

【正确答案】 B

【答案解析】Vitamins C, B₆, and B₁₂ are necessary for collagen synthesis that takes place during wound healing. Folate enables oxygen transport. Vitamin A is needed for reversal of effects of the glucocorticoids. Thiamine is required for carbohydrate metabolism.