Although Mark Realizes That His Behavior Is Unreasonable, He Is

Although Mark realizes that his behavior is unreasonable, he is so alarmed by high bridges or expressway overpasses that he avoids them by taking an unnecessarily lengthy route to and from work each day. Mark appears to suffer from

A) obsessive-compulsive disorder.
B) posttraumatic stress disorder.
C) a phobia.
D) generalized anxiety disorder.