Complete This Statement: a Major Difference Between the Aldol

Complete this statement: A major difference between the Aldol condensation and the Claisen condensation reactions is that

A) the Aldol reaction involves substitution while the Claisen reaction involves addition.
B) the Aldol reaction is acid catalyzed while the Claisen reaction is base-catalyzed.
C) the Aldol reaction is base catalyzed while the Claisen reaction requires a full equivalent of base.
D) the Aldol reaction is base catalyzed while the Claisen reaction is acid-catalyzed.