There are two supposedly conflicting hypotheses as to what makes for great national leaders: one is that such leaders successfully shape public opinion, and the other is that they are adept at reacting to it. However, treating these hypotheses as mutually exclusive is evidently a mistake. All leaders who have had success getting their programs passed by their country' s legislature have been adroit both in shaping and reacting to public opinion. Which one of the following is an assumption on which the argument depends? ['Having success getting programs passed by the legislature is indicative of being a great national leader.', 'It is impossible to successfully shape public opinion without in some way reacting to it.', 'To lead, one must either successfully shape public opinion or be adept at reacting to it, or both.', 'Having a good rapport with the members of the legislature allows a leader to shape public opinion.']