The order of difficulty from the hardest to the easiest would be subject to the concept we have of Torque.
The Torque principle defines us that
Where,
F = Force
d = Distance
As the distance increases, the force applied must be less to make the movement of the object so we have to
Hence we have to be the distance inversely proportional to the force to turn the door the order would be:
As close to the hinges as possible (Hardest)> The center of the door> the edge farthest from the hinges (Easies)
1>2>3