This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
The monoclonal antibody useful in the treatment of PNH is: 
Select and explain. 
A. Rituximab, B. Eculizumab, C. Infliximab, D. Adalimumab
B: Eculizumab
Answer: B: Eculizumab 
Explanation: By blocking the complement cascade downstream of C5, eculizumab abolishes complement-dependent intravascular hemolysis in all PNH patients, and significantly improves their quality of life. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 884