(a) A person commits the crime of burglary in the first degree if the person violates AS 11.46.310 and (1) the building is a dwelling; or
(2) in effecting entry or while in the building or immediate flight from the building, the person (A) is armed with a firearm;
(B) causes or attempts to cause physical injury to a person; or
(C) uses or threatens to use a dangerous instrument.
(b) Burglary in the first degree is a class B felony.