Columnist: Almost anyone can be an expert, for there are no official guidelines determining what an expert must know. Anybody who manages to convince some people of his or her qualifications in an area -- whatever those may be -- is an expert. The columnist's conclusion follows logically if which one of the following is assumed? ['Every expert has convinced some people of his or her qualifications in some area.', 'Convincing certain people that one is qualified in an area requires that one actually be qualified in that area.', 'Some experts convince everyone of their qualifications in almost every area.', 'Almost anyone can convince some people of his or her qualifications in some area.']