This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
Which of the following is approved for the treatment of cystic fibrosis with G551D mutation? 
Select and explain. 
A. Biostrophin, B. Peginesatide, C. Lumacaftor, D. Ivacaftor
D: Ivacaftor
Answer: D: Ivacaftor 
Explanation: Biostrophin is a vehicle for gene therapy in Duchenne and Becker's muscular dystrophyPeginesatide is an erythropoietin analog for anemia of chronic kidney diseaseLumacaftor is a CFTR potentiator for cystic fibrosis with F508 mutationIvacaftor is a CFTR potentiator for cystic fibrosis with G551D mutation