Which BEST describes the effect of confining the story's action to an hour's time? A) It allows the reader to understand how quickly everything can change in one's life. B) None of these choices describe the effects of confining the story's action to an hour. C) It allows the reader to understand that the characters will in fact live long, happy lives. D) It allows the reader to flashback to an earlier time to better understand the feelings of the characters.

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?