Sentence Correction

I have a question about the meaning in SC.
The A) answer in the sentence describes a situation. Is it possible that the grammatically right answer does not have the same meaning?
At the same time, I wonder which sentence is the reference in the meaning, the one which is in the original sentence, the A) ?

For example:
Organized in 1966 by the Fish and Wildlife Service, the Breeding Bird Survey uses annual roadside counts along established routes for monitoring of population changes of as many as, or of more than 250 bird species, including 180 songbirds.
A) for monitoring of population changes of as many as, or
C) to monitor changes in the population of

When two answer choices are gramatically correct, one should go for the choice, which does not alter the intent of the question stem. You can find more details in Spidey's correction notes.

In this case, A is unncessarily wordy. " as many as, or more than" -this is something equivalent to equal to or more than a number..But the intended meaning in question stem stresses that more than 250 species is the matter of concern.