I chose E for this question because I thought that the research discussed in line 20 could also be the "literature on purple loosestrife control," but would this answer be wrong because the purple loosestrife literature discussed in B doesn't explicitly mention that it's on the control of purple loosestrife?
Alternately, could someone explain why A is correct? I was initially hesitant because of the "furbearer productivity" mentioned in Passage A vs. the "furbearing animals" mentioned in Passage B. Would furbearer productivity be the same thing as furbearing animals? Aren't they talking about the productivity of furbearers in particular?