A.
If the humidifier contains UN3159 Refrigerant Gas R134a, Special Provisions A103 nor A26 would apply, and therefore, it should be treated as a dangerous goods.

If the humidifier falls under the definition of UN2857 Refrigerating machine containing non-flammable non-toxic gas, Special Provision A26 May apply where if Div. 2.2 gas is less than 12kg, the humidifier can be shipped as being not restricted.

The humidifier would not be classified as UN3358 Refrigerating machine containing flammable non-toxic liquefied gas, however if the gas contained is Div. 2.1, it May then be classified as not dangerous provided the gas is less than 100g.