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 commonest cause of death in a patient with primary amyloidosis is - 
Select and explain. 
A. Renal failure, B. Cardiac involvement, C. Bleeding diathesis, D. Respiratory failure
B: Cardiac involvement
Answer: B: Cardiac involvement 
Explanation: None