When new york university women were dressed in ku klux klan–style hoods, they demonstrated significantly more aggression. this finding is best explained in terms of?

It is called deindividuation. It is a concept of social psychology and it shows the loss of self-awareness. Deindividuation theory tries to analyze antinormative collective behavior, such as violent crowds, lynch mobs etc. There is a model called SIDE (social identity model of deindividuation effects), which provides an alternative explanation for the deindividuation. The model suggests that anonymity has a profound effect on a group behavior. 

Ithink it's a, but i might be wrong