单选题 The FBI official has NOT admitted that ______.

A、 the canisters were fired at the main structure
B、 the canisters were fired hours before the fire started
C、 federal agents fired tear gas canisters capable of causing a fire
D、 other tear gas canisters that were not flammable or potentially explosive were also used

【正确答案】 A

【答案解析】根据文中“the law enforcement official said the canisters were fired not at the main structure—but at the nearby underground bunker．”这一句可以看出A是他没有承认的内容，而B，C和D都在文中有直接或间接的体现。