A person is guilty of burglary in the second degree when he knowingly enters or remains unlawfully in a building with intent to commit a crime therein, and when:

1. 1. In effecting entry or while in the building or in immediate flight therefrom, he or another participant in the crime:

   1. (a) Is armed with explosives or a deadly weapon; or
   2. (b) Causes physical injury to any person who is not a participant in the crime; or
   3. (c) Uses or threatens the immediate use of a dangerous instrument; or
   4. (d) Displays what appears to be a pistol, revolver, rifle, shotgun, machine gun or other firearm; or
2. 2. The building is a dwelling. Burglary in the second degree is a class C felony.