The correct option is C KCN
C2H4Cl2 is formed from three non-metals that are carbon, hydrogen, and chlorine. Thus, the bond is covalent.
CH3I is formed from three non-metals that are carbon, hydrogen and iodine. Thus, the bond is covalent in this case too.
KCN is formed from two non-metals that are carbon and nitrogen and one metal that is potassium.
Ionic bond is formed between K+ and the CN− and covalent bonds are formed between N and C.
H2O2: It is composed of two elements hydrogen and oxygen which form covalent bonds.