Artistic success as an actor is directly dependent on how well an actor has developed his craft. This has been demonstrated by the discovery of a positive relationship between the number of classes taken by an actor and the number of professional production in which that actor has appeared in the past two years.

Each of the following, if true, casts doubt on the author's argument about artistic success for actors EXCEPT:

(A) The figures for the number of classes taken were based solely on the information provided by actors.
(B) Success as an actor cannot necessarily be judged exclusively by recent credits.
(C) For most successful actors, it is not the quantity but the quality of their classes that helped to develop their craft.
(D) There is no relationship between the number of professional productions in which an actor has appeared and true artistic success.
(E) Most successful actors have taken only a small number of intensive classes

Consued