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
What is the drug of choice for CMV (cytomegalovirus) retinitis in patients with AIDS 
Select and explain. 
A. Acyclovir, B. Ganciclovir, C. Pentamidine, D. Cotrimoxazole
B: Ganciclovir
Answer: B: Ganciclovir 
Explanation: None