一道LSAT题目，我有点晕...

The function of government is to satisfy the genuine wants of the masses, and government cannot satisfy those wants unless it is informed about what those wants are. Freedom of speech ensures that such information will reach the ears of government officials. Therefore, freedom of speech is indispensable for a healthy state.
Which one of the following, if true, would NOT undermine the conclusion of the argument?
(A) People most often do not know what they genuinely want.
(B) Freedom of speech tends ultimately to undermine social order, and social order is a prerequisite for satisfying the wants of the masses.
(C) The proper function of government is not to satisfy wants, but to provide equality of opportunity.
(D) Freedom of speech is not sufficient for satisfying the wants of the masses: social order is necessary as well.
(E) Rulers already know what the people want.

So based on my understanding, A---satisfy the wants of the masses; B---government is informed; C---freedom of speech, the logic reasoning will be:

A--->B; B--->C; so A--->C

the word "ensure" represent a sufficient condition or necessary condition?Confused...