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: Surgery
Anterior mediastinal tumors is/are -a) Thymomab) Aortic aneurysmc) Bronchogenic Cystd) Lymphomae) Bochdalek hernia 
Select and explain. 
A. acd, B. abd, C. abc, D. ab
B: abd
Answer: B: abd 
Explanation: None