This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition, Subject name: Medicine
Cobalt is a part of which vitamin - 
Select and explain. 
A. Retinol, B. Pyrodoxine, C. Cyanocobalamin, D. Vitamin C
C: Cyanocobalamin
Answer: C: Cyanocobalamin 
Explanation: Ans. is 'c' i.e., Cyanocobalamin o Cobalt is a part of Cyanocobalamine