Walter: Although cigarette smoking is legal, it should be banned on al

Walter: Although cigarette smoking is legal, it should be banned on all airline flights. Cigarette smoking in the confines of an aircraft exposes nonsmokers to harmful secondhand smoke that they cannot avoid.

Which one the following principles, if established, would justify the proposal put forth by Walter?

(A) People should be prohibited from engaging in an otherwise legal activity in those situations in which that activity would unavoidably expose others to harm. -- This is the correct choice because this aligns in tandem with Walter's proposal to ban an activity that is harmful and the sufferers have no recourse.

(B) An activity should be banned only if most situations in which a person engaged in that activity would inevitably expose others to harm. --- Harm caused in 'most situations' is untenable. Even if in one situation the harm cannot be avoided, it should be banned.

(C) A legal activity that has the potential for causing harm to others in certain situations should be modified in those situations to render it harmless. --It is not clear how well the modification is going to prevent the harm.

(D) People who regularly engage in an activity that has the potential for harming others when that activity takes place in certain situations should be excluded from those situations. --- Does not clarify what happens until they are excluded.

(E) If an activity is legal in some situations in which a person’s engaging in that activity could harm others, then that activity should be legal in all situations. -- Legality of an activity is not an issue in this argument