PT 27 S1 Q4

In Yasukawa's month-long study of blackbirds, the percentage of smaller ... ...

Which one of the following, if true, indicates that the criticism of Yasukawa's research is based on a misunderstanding of it?
(A) Yasukawa compared the survival chances of two different species of blackbirds, a larger and a small species, rather than of different sizes of birds within one species.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Weaker: Intro Set