The Magnetic effect of current was discovered by:
(A) John Ambrose Fleming
(B) Hans Christian Oersted
(C ) Michael Faraday
(D) Andre- Maria Ampere

Hint: According to the magnetic effect of current, a current carrying wire can cause a deflection in a magnetic needle. In the presence of a current through the wire that will deflect the needles of a compass. Thus we can say that the electric current and magnetism are related to each other.

Complete answer:
The Magnetic effect of current was discovered by Hans Christian Oersted. According to the magnetic effect of current, a current carrying wire can cause a deflection in a magnetic needle. In the presence of a current through the wire that will deflect the needles of a compass. Thus we can say that the electric current and magnetism are related to each other. The effect of current which produces a magnetic effect is thus known as an electromagnetic effect.
The magnetic electricity is discovered by Michael Faraday. According to Michael Faraday, the magnet through a wire, causes an electric current. John Ambrose Fleming established right hand rule. Whereas, Andre- Maria Ampere is one of the founders of classical electromagnetism.

Thus option (B ) is correct.

Note:
Thus the Magnetic effect of current was discovered by Hans Christian Oersted. According to the magnetic effect of current, a current carrying wire can cause a deflection in a magnetic needle. In the presence of a current through the wire that will deflect the needles of a compass. Thus we can say that the electric current and magnetism are related to each other. The magnetic electricity is discovered by Michael Faraday. According to Michael Faraday, the magnet through a wire, causes an electric current. John Ambrose Fleming established right hand rule. Whereas, Andre- Maria Ampere is one of the founders of classical electromagnetism.