GMAT Reading Comprehension (RC) | Re: The golden toad of Costa Rica, whose beauty and rarity

Can someone please explain , why Option B for Q4 is incorrect ? . When it is clearly stated in the passage "it is now apparent that setting aside habitat was not enough to save this beautiful creature."

Also I mostly end up doing inference questions wrong . Any advice/tips on how to attack an inference question would be very helpful.

Thanks !

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