The region around a magnetic material or a moving charge particle is called magnetic field. The direction of magnetic field line is given by right hand thumb rule.
The thumb denotes the direction of electric current, then the curled finger will show the direction of magnetic field.
For a straight wire, the direction of magnetic field lines are circular.
The answer to this is C. The reason being is because if you were to use a compass then it would be making circular motions towards the middle of the wire.
