C. The court or jury shall determine whether, by clear and convincing evidence, the respondent is a sexually violent predator. If the court or jury does not find clear and convincing evidence that the respondent is a sexually violent predator, the court shall, in the case of a prisoner, direct that he be returned to the custody of the Department of Corrections. The Department of Corrections shall immediately release him if his scheduled release date has passed, or hold him until his scheduled release date. In the case of a defendant, if the court or jury does not find by clear and convincing evidence that he is a sexually violent predator, the court shall order that he be discharged, involuntarily admitted pursuant to §§ 37.2-814 through 37.2-819, or certified for admission pursuant to § 37.2-806. If he meets the qualifications set forth in subsection B of § 37.2-904 or 37.2-907, any expert witness may be permitted to testify at the trial as to his diagnosis, his opinion as to whether the respondent meets the definition of a sexually violent predator, his recommendation as to treatment, and the basis for his opinions. Such opinions shall not be dispositive of whether the respondent is a sexually violent predator.