(1) A person is justified in the use of force or threat to use force against another when and to the extent that the person reasonably believes that the use of force is necessary to prevent or terminate the other person's unlawful entry into or attack upon an occupied structure.
(2) A person justified in the use of force pursuant to subsection (1) is justified in the use of force likely to cause death or serious bodily harm only if:
(a) the entry is made or attempted and the person reasonably believes that the force is necessary to prevent an assault upon the person or another then in the occupied structure; or
(b) the person reasonably believes that the force is necessary to prevent the commission of a forcible felony in the occupied structure.