Critical Reasoning

3. 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?
(A) Almost anyone can convince some people of
his or her qualifications in some area.
(B) Some experts convince everyone of their
qualifications in almost every area.
(C) Convincing certain people that one is qualified
in an area requires that one actually be
qualified in that area.
(D) Every expert has convinced some people of his
or her qualifications in some area.
(E) Some people manage to convince almost
everyone of their qualifications in one or
more areas

The answer is A.
whts the OA?

The official answer is A. But I don't understand why? Can anyone explain