When a fire__________at the National Exhibition in London, at le

When a fire__________at the National Exhibition in London, at least ten priceless paintings were completely destroyed.
A、broke off
B、broke out
C、broke down
D、broke up
【正确答案】：B
【题目解析】：break out意为“(战争#_#疾病)的突然发生”，符合句意。break off意为“中断，绝交”;breakdown意为“抛锚，出故障”;break up“打碎，分解”。