This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
The micronutrient, helping to increase the absorption of iron from the diet 
Select and explain. 
A. Folic acid, B. Ascorbic acid, C. Nicotinic acid, D. Pantothenic acid
B: Ascorbic acid
Answer: B: Ascorbic acid 
Explanation: Dietary composition affects the biologic availability and use of nutrients. For example, the absorption of iron may be impaired by large amounts of calcium or lead; likewise, non-heme iron uptake may be impaired by a lack of ascorbic acid and amino acids in the meal.Ref: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 95e; Nutrient Requirements and Dietary Assessment