Which of the following choices demonstrates how the writer creates the point that physical responses to stressful situations is part of human nature? a) the author compares a caveman physically responding to a tiger to a modern man physically responding to an unknown situation at work. b) the author examines the stressful situation people face today and concludes that they are much more stressful than those faced in the past. c) the author stresses that physical reactions to stress are always positive. d) the author explains that cavemen used their physical responses to survive.