GMAT Critical Reasoning (CR) | Re: Hunter: Many people blame hunters alone for the decline in

Hi Experts,
I have a couple of Qs for this argument:
a. Clarification in identifying main conclusion.
b. Is second part of (B) ie argument seeks to explain is correct?

Presenting my understanding:

Hunter: Many people blame hunters alone for the decline in Greenrock
National Forest???s deer population over the past ten years.

Here, hunter is the author of argument and the BF is belief of people.

Yet clearly, black bears have also played an important role in this decline.

Is this main conclusion
...

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