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
Richest source of Vitamin D - 
Select and explain. 
A. Milk, B. Egg, C. Halibut liver oil, D. Butter
C: Halibut liver oil
Answer: C: Halibut liver oil 
Explanation: Halibut liver oil contain 500-10,000 Microban per 100g . egg contain - 1 . 25microgram, Milk 0.1micrigram per 100g.REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 21ST EDITION. PAGE NO - 617