D. Stop polio immunization altogether.

Perhaps this will be possible some day soon. The problem is that there is still wildtype polio in isolated locations in Asia, and there are cVDPV outbreaks occurring in a few locations worldwide. It would be foolish to let our high level of immunity to polio decline until the disease has been formally declared eradicated worldwide (like smallpox). When this occurs, there will be no potential for reintroduction into the U.S., and polio vaccination could safely cease altogether.