A． Political protests during the Olympic
B． Security operations during the Olympic
C． Olympics' security force
D． Security measures in building
参考答案B
解析:主旨题。这篇新闻主要讲述了加拿大政府为温哥华冬奥会的安防工作投入了大量的人力和财力，可知答案为[B]。
