问题
Her house _____ at 6 o’clock this morning and it _____ for about an hour.[ ]
A: was on fire; caught fire
B: caught fire; was on fire
C: had caught fire; had been on fire
D: caught a fire; was on fire
B: caught fire; was on fire
C: had caught fire; had been on fire
D: caught a fire; was on fire
正确答案是：
