The author of passage B might agree with (C), but there is nothing in passage A that would suggest anything other than genuine concern. Remember on these reading comprehension questions, there has to be direct evidence within the passage for anything that you're answering.
The correct answer is (B) because both passages recognize and specifically reference the significant threat that purple loosestrife poses to aquatic furbearers. Lines 10-13 and Lines 55-58.
