Moving charges constitute
electric current
Explanation of correct option:
(b) The motion of charges produces an electric current.
Current is defined as the rate at which electrons flow past a point in an electrical circuit.
Explanation of incorrect option:
(a) An electrode is defined as an electrical conductor which is used to make contact with a nonmetallic part of a circuit.
(c) Static electricity is produced when two objects are rubbed together and charged particles are transferred from one surface to another.
(d) Magnetism is a magnetic property induced in the surrounding area of a magnet or current-carrying conductor.
Therefore, the correct option is (b).