Sentence Correction

Early ornithologists often mistook the calling of the Mockingbird as the rare Rufous Sided Towhee

A. calling of the Mockingbird as the rare Rufous Sided Towhee
B. call of the Mockingbird for that of the rare Rufous Sided Towhee
C. call of the Mockingbird as the rare Rufous Sided Towhee
D. calling of the Mockingbird for that of the rare Rufous Sided Towhee
E. Mockingbird calling for the rare Rufous Sided Towhee

OA: A

Why is call preferred over calling?

IMO answer choice B is right as the idiom is rightly constructed "mistook X for Y"
But you say the OA is : A

Im pretty confused