(a) A person is guilty of assault in the third degree when: (1) With intent to cause physical injury to another person, he causes such injury to such person or to a third person; or (2) he recklessly causes serious physical injury to another person; or (3) with criminal negligence, he causes physical injury to another person by means of a deadly weapon, a dangerous instrument or an electronic defense weapon.

(b) Assault in the third degree is a class A misdemeanor and any person found guilty under subdivision (3) of subsection (a) of this section shall be sentenced to a term of imprisonment of one year which may not be suspended or reduced.