Fred Has Been Having a Great Deal of Trouble Initiating

Fred has been having a great deal of trouble initiating and maintaining sleep. He guesses that he is sleeping for an average of about three hours each night and complains that he feels terrible during the day. In addition, Fred has always experienced some anxiety but has recently felt a tremendous increase in his overall anxiety level. The existence of both a sleep disorder and anxiety

A) makes the diagnosis of primary insomnia incorrect.
B) increases our confidence that primary insomnia is the correct diagnosis.
C) indicates that the insomnia is a result of the anxiety rather than a cause of the anxiety.
D) is extremely common, since sleep problems can be both a cause and a result of anxiety.