The question is asking what the author is most likely to believe about the view that "we base our inferences about what we ourselves are thinking solely on observations of our own external behavior" (lines 44-46). When we refer to the passage, we see the lines immediately following the introduction of this claim state "but, in fact, their arguments do not commit them to this claim" (lines 46-47) and proceed to describe how the inferences are based on "internal cognitive activity" (lines 49-50) rather than external behavior. Therefore, it is clear that the other disagrees with this view.
(D) states that the author believes the view "seems to contradict common sense but is basically sound." This does not match the author's disagreement with the view, which implies that the author does not believe the view is "basically sound." If the author did believe the view was sound, the author would likely agree with it. Therefore, (D) is incorrect.
(E) states that the author believes the view "is not considered to be an intellectually defensible position." This matches the author's dismissal of the view in exchange for a different, assumedly more defensible explanation. Therefore, (E) is correct.
Does this make sense? Please let us know if you have any additional questions!