Sandy lives on the top floor of a 10-story building in a bigcity. There is a 30-

Sandy lives on the top floor of a 10-story building in a bigcity. There is a 30-story apartment building under constructionnext door to her building. One morning while eating her cornflakes a brand new toilet comes crashing through the roof ofSandys apartment and injures her. She would like to sue theconstruction firm but has no way of finding out or proving whatpersons were involved or exactly what happened. The doctrine thatwould most help Sandy is: