The correct option is A I, II, and III
Polarizability of an anion depends upon the size and the charge on the anion. Larger the size and greater the charge, more will be its polarizability.
(i) In S2− and Se2−, the anions have the same magnitude of charge but the size of Se2− is larger than that of S2−. Hence, the polarizability of Se2− is higher than that of S2−.
(ii) In S2− and Cl−, S2− has more negative charge than Cl− and also the size of S2− is larger than that of Cl−. Hence, the polarizability of S2− is higher than that of Cl−.
(iii) In S2− and P3−, S2− has less negative charge than P3− and also the size of P3− is larger than that of S2−. Hence, the polarizability of P3− is higher than that of S2−.
(iv) In S2− and O2−, S2− has the same negative charge as O2− but the size of S2− is larger than that of O2−. Hence, the polarizability of S2− is higher than that of O2−.