单选题 According to the article, a population explosion of elk and deer was caused also by ______.

A、 the adoption of a policy of aggressive predator elimination
B、 the increased number of Nation Parks
C、 the decreasing number of visitors to National Parks
D、 the heavy exploitation of endangered animals in the 20 century

【正确答案】 A

【答案解析】由Complicating the problem，…adopted a policy of aggressive predator elimination，thus reducing natural wildlife population control．可见侵略性的捕掠的消失使问题更加复杂。所以A是正确答案。