Your friend Tom knows that you are taking a psychology class, so over lunch one day he tells you of a "bad habit" he has that has persisted for a couple of years. He says that when he gets dressed in the morning he puts on and takes off his pants at least a hundred times, because each time he puts one leg into the pants, the other leg needs to be "evened out." This behavior pattern has caused him to be late for classes and work, as well as to cause him overall distress. You suspect Tom is suffering from _____ disorder.
A. posttraumatic stress
B. generalized anxiety
C. obsessive-compulsive
D. rechecking

Obsessive-Compulsive disorder is a psychological problem or disorder. This type of disorder affects all age group people as well as male, female both.

Obsession is intrusive and unwanted.
The urge is intensively affected and distressing the feelings.
Compulsion is a behavior in which a person is en ganged.
Many people have both obsession and compulsion.
People engage in behavior so that they can rid themselves of this mental problem.

Thus here Tom has a bad habit and he was engaging in this type of behavior. Tom was suffering from an obsessive-compulsive behavioral disorder.