This is the best way I could think of people getting into the dangerous areas.A. stopping

问题补充：

This is the best way I could think of people getting into the dangerous areas.

A. stopping

B. to keep

C. to stop

D. keeping

答案：

A. stopping

B. to keep

(答案→)C. to stop

D. keeping

解析：考查非谓语动词。句意：这是我能想到的最好的办法来阻止人们进入危险地区。不定式做状语表示具体的将要进行的动过，keep是维持的意思，故选C。