This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Enzymes, Subject name: Biochemistry
Copper-containing enzyme is 
Select and explain. 
A. Cytochrome synthase, B. Catalase, C. LDH, D. None
A: Cytochrome synthase
Answer: A: Cytochrome synthase 
Explanation: Cytochrome oxidase contains 2 heme groups and 2 copper ions. The two heme groups are denoted as cytochrome-a and cytochrome a-3. The functional unit of the enzyme is a single protein and is referred to as cytochrome a--a3.Ref: DM Vasudevan, Page no: 230