Which is not a factor in why other people create arousal in us? apprehension distraction mere presence vanity?

The correct option is VANITY.
In psychology, arousal refers to the state of been stimulated to a point of perception. It is controlled by the part of the brain called Reticular Activating System. Arousal is brought about by a number of different things such as emotions, food, sounds, etc. Other people can create arousal in us in different ways such by their presence, apprehension and distraction. Arousal may enhance performance or decrease it. 

The type of rock she find is a sediment rock