According to Fajan's rule; covalent character in ionic compound depends on (i) size and charge of cation (ii) size and charge of anion (iii) pseudo-inert gas configuration (a). Size of iodide (I−)is more than F*, so I−has more polarisibility. Thus, KI is more covalent than KF. So, option (a) is incorrcct. (b) Charge on Sn in SnCl4 is +4 and in SnCl2 is +2 So. Sn has more polarising power in SnCl4. Thus, SnCl4 is more covalent than SnCl2. So, option (b) is incorrect. (c) Size of Li+is less than K+⋅So, it has more polarising power. Thus, LiF is more covalent than KF. Hence, option (c) is correct. (d) Charge on Zn is +2 and on Na is +1. So, Zn has more polarising power. Thus, ZnCl2 is more covalent than NaCl. Hence, option (d) is incorrect.