Answer:
I think it's b but I'm not sure sorrt
I would say B. to have a thorough knowledge of grammar
The correct answer is B. They suspect something strange may be going on.
Explanation
According to the fragment, it can be inferred that the central theme of the discussion between Charlie and Steve is about a strange fact that caught their attention and they are going to check what has happened. In addition, they discard the option that it was a meteorite as Steve says "It couldn't be the meteor. A meteor couldn't do this". According to the above, the correct answer is B because they can not explain the event that just happened.
