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: Pharmacology
Which of the following is active against atypical mycobacteria - 
Select and explain. 
A. Clarithromycin, B. Rifabutin, C. Ciprofloxacin, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. is 'd' All of the above Regimen for MAC infection o Intensive phase (2-6 months) --> Clarithromycin/Azithromycin + ethambutol + rifabutin + one FQ (ciprofloxacin)/ clofazimine. o Maintenance phase (12 months) -4 Clarithromycin/ azithromycin + ethambutol/one FQ/rifabutin.