What is the size of the winding, shown in the figure?

The correct  answer is option 2):(Concentric winding)

Concentrated winding :

• Concentrated winding is employed where the number of slots on the armature is equal to the number of poles in the machine.
• This armature winding of the alternator gives maximum output voltage but not exactly sinusoidal.
• The most simple single-phase winding is shown below in the figure. Here, the number of poles = number of slots = number of coil sides.
• Here, one coil side is inside one slot under one pole, and the other coil side inside the other slot under the next pole. The emf induced in one coil side is added to that of the adjacent coil side.

• The above given picture is concentric winding