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 3 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.