The author explains the "fight or flight" response by comparing and contrasting a) humans to tigers b) workers to bosses c) modern man to cavemen d) adrenalin to heart failure

Probably too late, but I just read the selection. It's A, because the "fight or flight response" in the passage comes down to your boss asking to see you in his office. Of course, also in the passage, this is a false alarm. However, it is A because it activated, and as in the passage stated it's activating the same power your "stone age ancestors" used to fight sabre-tooth tigers.