Answer:
The easiest one to correct would most likely be Class V, since in this type of mutation, the only problem or abnormality is the production of insufficient amounts of the needed CFTR.
Step-by-step explanation:
Mutation Classes
Class I - Gene contains a stop signal that prevents CFTR from being made.
Class II - CFTR is made, but does not reach the cell membrane
Class III - CFTR is made and in the right place, but does not function normally
Class IV - Channel does not move substances efficiently or at all
Class V - CFTR is made in smaller than normal quantities