In the right-hand thumb rule for current-carrying wire the thumb points toward the:

The correct answer is: Direction of the flow of current.

• When we pass electric current to a straight current-carrying conductor, it produces a magnetic field around it. At every location along the current-carrying conductor, the field lines take the shape of concentric circles.
• The Right-Hand Thumb Rule, also known as the Maxwell Corkscrew Rule, can be used to determine the direction of the produced magnetic field which is in proportion to the flow of electric current through a straight conductor.
• According to this rule, if a current-carrying conductor is held by the right hand with the thumb kept straight and if the electric current is flowing in the thumb's direction, the direction in which the remaining fingers are wrapped will reveal the direction of the magnetic field.