A. A person commits arson of a structure or property by knowingly and unlawfully damaging a structure or property by knowingly causing a fire or explosion.
B. Arson of a structure is a class 4 felony. Arson of property is a class 4 felony if the property had a value of more than one thousand dollars. Arson of property is a class 5 felony if the property had a value of more than one hundred dollars but not more than one thousand dollars. Arson of property is a class 1 misdemeanor if the property had a value of one hundred dollars or less.