1. A person commits the offense of assault in the second degree if he or she:
(1) Attempts to kill or knowingly causes or attempts to cause serious physical injury to another person under the influence of sudden passion arising out of adequate cause; or
(2) Attempts to cause or knowingly causes physical injury to another person by means of a deadly weapon or dangerous instrument; or
(3) Recklessly causes serious physical injury to another person; or
(4) Recklessly causes physical injury to another person by means of discharge of a firearm.
2. The defendant shall have the burden of injecting the issue of influence of sudden passion arising from adequate cause under subdivision (1) of subsection 1 of this section.
3. The offense of assault in the second degree is a class D felony, unless the victim of such assault is a special victim, as the term "special victim" is defined under section 565.002, in which case it is a class B felony.