(a) Causes serious physical injury to the victim of such crime; or
(b) Uses or threatens the immediate use of a dangerous instrument; or 2. He or she has engaged in conduct constituting the crime of rape in the first degree, criminal sexual act in the first degree, aggravated sexual abuse in the first degree, or course of sexual conduct against a child in the first degree, as defined in this article, against one or more additional persons; or 3. He or she has previously been subjected to a conviction for a felony defined in this article, incest as defined in section 255.25 of this chapter or use of a child in a sexual performance as defined in section 263.05 of this chapter. Predatory sexual assault is a class A-II felony.