This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CLL & CML, Subject name: Medicine
Which has worst prognosis in CLL? 
Select and explain. 
A. 11q Deletion, B. 12q Trisomy, C. 17p Deletion, D. 13q Deletion
C: 17p Deletion
Answer: C: 17p Deletion 
Explanation: 13q deletion : Indolent course ; good prognosis Trisomy 12 : Intermediate prognosis 11q deletion : Poor prognosis 17p deletion : Poorest prognosis