Answer:
The correct answer is option C.
Step-by-step explanation:
When fan starts the fan blades also starts spinning around axle.The axle represent the nucleus and the uniform donut like shape(with slightly fade color) formed by the movement of blades represents the electron cloud around the nucleus.
Schrodinger proposed the quantum mechanical model of the atom in which he defined the location of electrons inside an atom by electron cloud in 3-d space (as shown in the figure).