While ________ for the bus at the bus station, I met an old frie

While ________ for the bus at the bus station, I met an old friend of mine whom I haven't seen for 10 years.
A、being waited
B、waiting
C、having waited
D、waited
【正确答案】：B
【题目解析】：wait 在这里为非谓语，做伴随状语，使用现在分词形式，waiting