The writer decides to write about something that happened years back, therefore, his style, diction will be related to that era/time.
For example, a contemporary writer that wants to write about Victorian era must place the events in the book in the right historical context i.e one can't see certain words and expressions, and the characters can't wear leather strap blouses or live in condos.
1) D This is because we are waiting to see what will happen now that they will no longer stay silent and be oppressed. 2) B Because the thermometer changed much in society. Hope this helps!