During the Cuban Missile Crisis, President John F. Kennedy's primary demand was for the removal of all existing Soviet missiles from Cuba. He sought to ensure that no further missile deliveries would take place and that the threat posed by these missiles would be eliminated. Therefore, the correct answer would be "all existing missiles must be removed."
The other options you mentioned, such as a planned invasion of Cuba, permanently closing Cuban airports, or demands about cigars, were not part of Kennedy's formal demands during the crisis.