A)All the passengers were killed.
B)The plane crashed in the night.
C)No more survivors have been found.
D)It's too late to search for survivors.
原文：
1.W: Is the rescue crew still looking for survivors of the plane crash?
M: Yes, they have been searching the area for hours, but they haven't found anybody else. They will keep searching until night falls.
Q: What do we learn from the conversation?