mark was with one of his friends when that friend was struck and killed by a car. in recent days, he has found himself having painful and vivid flashbacks to the event, increasing irritability, guilt, sleeplessness, and an emotional numbing. to handle these feelings, he has realized that he has been drinking more heavily than usual, which worries him and has brought him to see the psychologist?group of answer choices based on this evidencea. the psychologist would likely conclude that mark has a substance abuse disorder b. mark most clearly seems to be suffering from depression c. mark shows the signs of having a post-traumatic stress disorder (ptsd) d. mark suffers from obsessive-compulsive disorder