During the excitement and stimulation of a large Mardi Gras street party, normally circumspect, law-abiding citizens wearing masks engage in uninhibited and even illegal behavior. This BEST reflects the social psychological phenomenon of:

The correct answer to this open question is the following.

Although there are no options provided, we can say the following.

During the excitement and stimulation of a large Mardi Gras street party, normally circumspect, law-abiding citizens wearing masks engage in uninhibited and even illegal behavior. This BEST reflects the social psychological phenomenon of anonymity.

These people have masks that cover their true identity, so in theory, nobody can recognize them. That is why they act in strange ways or their behavior is questioned. These can be ordinary, decent people that have families and jobs. But when they appear in public places in anonymity, they transform themselves. And more, if they are drunk because they are attending a Mardi Gras street party, they indeed can act in very strange ways under the influence of alcohol.