The basic concept of how a simple motor works is explained by the statement that D) When a wire that carries electrical current is placed in a magnetic field, the wire experiences a force.
Explanation:
When a wire carries an electric current the wire becomes electromagnetic and when this wire is placed in a magnetic field ,then a magnetic repulsive force is created  which is known as the Lorentz Force
In simple words when a current flows through a conductor (Like wire) the conductor starts acting like a magnet ,and when we place this magnet in  a magnetic field Lorentz Force is created .This is the basic principle behind the working of the electric motors
So we can say that The basic concept of how a simple motor works is explained by the statement that D) When a wire that carries electrical current is placed in a magnetic field, the wire experiences a force.
