This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and health, Subject name: Social & Preventive Medicine
Minimal level of iodine at consumer level should be ________ppm - 
Select and explain. 
A. 5, B. 10, C. 15, D. 30
C: 15
Answer: C: 15 
Explanation: Level of iodine should be not less than 30ppm at the production point and is not less than 15ppm at consumer level.REF.PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE.Editon-21.Page no.-595