The correct answer is C.
The methods that can be used to influence the public opinion are A and B, as both contribute to shape an image of the party and its policies on the audiencie's minds. Although both serve the same purpouse, mechanism A is more explicit while mechanism B is a bit more subliminal but still a very effective propaganda tecnique.
On the other hand, mechanism C can be used by a faction within the party to gather power, but not to obtain external support.