Answer
See explanation.
Work Step by Step
The point of an air conditioner is to cool the entire room. Leaving the unit on the floor is ineffective because the heat that is drawn out of the “inside” is soon expelled to the “outside”, which is the same space. Moreover, the air conditioner motor itself exhausts even more heat, so the net result is to heat up the room.
The point of a refrigerator is to cool down a compartment inside the fridge. It is OK to exhaust that heat to the rest of the room.
