Em dashes are meant to indicate brief pauses within a running sentence. If you were to include one within a quote, it would go wherever a person pauses for an extended period of time (at least longer than the person would normally take to start their next word).
In your first answer choice, the reader is put under the impression that the em dashes used between "I", "uh", and "am" are pauses, as if Carla was at a brief loss for words. Since she likely paused and said "uh" while thinking of the next thing to say, this is the correct use of the em dash.
In your second answer choice, an em dash wouldn't be appropriate. It's not likely that Bianca would stop her sentence midway, pause, then tell Nawal to duck before the frisbee would hit his head. She likely stopped her sentence and immediately told him to duck instead.
In your third answer, this sentence doesn't even require a dash anywhere. There isn't a need for a pause between "shrieked" and "Laura".
In your fourth answer, this is also an incorrect use of an em dash. There wouldn't be a dash before "exclaimed" in this sentence.
Della becomes suddenly nervous about what Jim will think about her hair and how she will tell him how she sold it. She is unsure whether Jim will become cross with her.
If you are a selfabsorbed person who cares little for others you will hit the 5 people and blame it on the car and say it was not your fault it is a self driving car and there was nothing you could do. If you are a compationite person you will go and hit the tree and say you rather hit the tree then 5 people hoping the crash would not kill you.
