The compound that results from the formation of an ionic bond is:
C. NaCl
Sodium chloride (NaCl) is formed when sodium (Na) donates an electron to chlorine (Cl), resulting in the formation of Na⁺ and Cl⁻ ions, which are held together by electrostatic forces in an ionic bond.
The other compounds listed (H2O, NO2, and CO2) involve covalent bonding rather than ionic bonding.