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
Unilateral clubbing seen in -a) Samilial clubbingb) Pancoast tumorc) Pulmonary A-V fistula  d) Aortic aneurysm (arch)e) Congenital cyanotic heart ds. 
Select and explain. 
A. bcd, B. acd, C. ac, D. bd
A: bcd
Answer: A: bcd 
Explanation: None