(a) A person commits the crime of burglary in the first degree if the person violates AS 11.46.310 and

1. (1) the building is a dwelling; or

2. (2) in effecting entry or while in the building or immediate flight from the building, the person

   1. (A) is armed with a firearm;
   2. (B) causes or attempts to cause physical injury to a person; or
   3. (C) uses or threatens to use a dangerous instrument.