Although Clancy is a well-respected neurologist, his recent

Although Clancy is a well-respected neurologist, his recent critique in the American Neurology Review of Holmes's new popular book of strange but true neurological cases is unjustified. Holmes describes a number of cases of people who lose the ability to speak normally and can only communicate through song. Clancy critiques Holmes' approach as "voyeuristic" and "patronizing," but it is the same approach Holmes applied in all his previous best-selling books, and this latest book is on track to become the top seller of them all.
The argument's reasoning is most open to criticism on the grounds that it:
Choices
A
Attacks Clancy's credentials without any basis.
B
Assumes that if a book is popular, the author's approach must be justifiable.
C
Takes for granted the unlikely proposition that there are some people who can only communicate through song..
D
Attacks the character of the author rather than challenging the validity of the methods used.
E
Assumes that if Holmes' approach was valid for one of his books, it must have been valid for all of his books.