An example of a perfect diamagnet a superconductor .This implies that when a superconductor is put in a mangetic field of intensity B ,the magnetic field $\;B_{s}\;$ inside the superconductor will be such that :

Question

$(a)\;\normalsize B_{s}=-B\qquad(b)\;B_{s}=0\qquad(c)\;B_{s}=B\qquad(d)\;B_{s} < B \;but\;B_{s} \neq 0$