Which one of the following conclusions was established by Oersted’s experiment conducted in 1820?
a) A steady electric current produces a magnetic field only if the conductor is wound into a coil.
b) A varying electric current is required to produce a magnetic field around a conductor.
c) A steady electric current produces a magnetic field around the conductor.
d) A steady electric current produces an electric field around the conductor but the magnetic field exists only inside the wire.