If S1, S2, S3 and S4 are the solubilities of AgCl in water, in 0.01 M CaCl2, in 0.01 M NaCl and in 0.05 M AgNO3 respectively at a certain temperature, the correct order of solubility is
(a) S1 > S2 > S3 > S4
(b) S1 > S3 > S2 > S4
(c) S1 > S2 = S3 > S4
(d) S1 > S3 > S4 > S2
