This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
A 72-year-old woman, in otherwise good health, presents with megaloblastic anemia. Careful evaluation reveals a folate deficiency as the cause of the anemia. Assuming the folate deficiency is due to dietary causes, which of the following is the most likely problem? 
Select and explain. 
A. Lack of leafy green vegetables, B. Lack of milk products, C. Lack of yellow vegetables, D. Overcooked food
D: Overcooked food
Answer: D: Overcooked food 
Explanation: Folates (pteroylglutamic acid and related compounds) are widely distributed in foodstuffs. Dietary deficiency is usually due to overcooked (folates are very labile) and old (folates rapidly decay with time) food.