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: Pathology
Most common type of class II mutation in cystic fibrosis is 
Select and explain. 
A. Missense mutation, B. Frameshift, C. Non sense, D. Deletion
D: Deletion
Answer: D: Deletion 
Explanation: Ans. D. DeletionClass II mutation : 'Deletion' of phenylalanine amino acid so CFTR protein fails to reach cell membrane