The basic concept of how a simple motor works is explained by which statement?

When current is flowing through the conductor that is placed in a magnetic field there is a force acting on the conductor. This force is called the Lorentz force, and in fact, whenever you have a charge moving in the magnetic field there is a force acting on it that is perpendicular to its motion. Lorentz force is very interesting as it does not change the speed of the charge only its direction.
In a conductor, there is a constant motion of electrons and if you put them in the magnetic field you get the force. 
Electromotor always has a static part, which is just a permanent magnet, and it has the conductor. I attached a sketch of a very simple electromotor.
If you trace the current along the conductor you will notice that for some part it is moving away from you and for some part, it is moving towards you. Because of this the forces on opposite sides of the conductor act in the opposite directions and create the torque that makes the conductor rotating.
The basic statement could be something like this:
When there is a current flowing through the conductor it acts as a magnet. If you put that conductor in the permanent magnetic field there will be a force that acts on it. If you carefully arrange the shape of the conductor you can achieve continual motion.

As newton's first law states a object in motion stays in motion