听一段材料，回答下面几个小题。
How many people were killed in the gas explosion?
A. At least 4.
B. Over 40.
C. About 30.
What happened early on Saturday morning?
A. A Russian rocket was sent up.
B. A tour bus slid off a highway.
C. Three aid workers were killed.
Where are the students from?
A. Paris.
B. California.
C. Boston.