Greg Seems to Be Preoccupied with the Possibility That He

Multiple Choice

Greg seems to be preoccupied with the possibility that he might miss an important message from someone in his family. He checks for new messages on his answering machine every 15 minutes. Greg's constant checking for messages could be considered an example of

A) an obsession.
B) a hallucination.
C) a delusion.
D) a compulsion.