听一段材料，回答下面几个小题。
How many news headlines are broadcast?
A．4．    B．5．    C．6．
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．
How many people were killed in the gas explosion?
A．At least 4．
B．About 30．
C．Over 40．