Which statement best explains why sodium bromide is classified as an ionic compound?

• A. Sodium and bromine form a metallic lattice with delocalized electrons.
• B. Sodium and bromine share electrons equally to form a nonpolar covalent bond.
• C. Sodium transfers an electron to bromine, forming ${\mathrm{Na}}^{+}$ and ${\mathrm{Br}}^{-}$ that are held together by electrostatic attraction.
• D. Sodium bromide consists of discrete molecules held together by hydrogen bonding.

Answer: (C)