Edgar Proposed a Theory to Explain Children's Learning

Edgar proposed a theory to explain children's learning.Over the years,several other researchers have tested Edgar's theory,with mixed results.In recent years,nearly every attempt at validation has resulted in disconfirmation of Edgar's theory.At this point,what should Edgar do?

A) continue to support his theory as it is, because a few disconfirmations do not mean very much
B) consider revising his theory, because the recent disconfirmations suggest that there may be problems with the theory
C) discard his theory altogether, because the recent disconfirmations prove that his theory is incorrect
D) critically evaluate the procedures used in the studies that failed to confirm his theory in an attempt to uncover flaws in the research procedures