Answer:
The correct criteria used is Periodization
Step-by-step explanation:
Periodization is the study that the historians use to categorize the past in blocks of time which have common characteristics so that is easily to remember them by. Usually done in order to make the study or analysis of these periods more easy.
Examples of the use of this term is when historians talk about the different ages and its different periods, like the contemporary era and the period of the cold war.