This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
Which one of the following are metalloporphyrins 
Select and explain. 
A. Cytochrome, B. Hemoglobin, C. Bilirubins, D. Catalase
A: Cytochrome
Answer: A: Cytochrome 
Explanation: (A) Cytochrome # Metalloporphyrins: Heme is the most important part of the metalloporphyrins Heme Chlorophyll Cytochromes Catalase Tryptophan pyrrolase