$\Delta_r H$ of which reaction correctly represents the lattice enthalpy of $NaCl_{(s)}$?

• A
  $NaCl_{(s)} \longrightarrow Na_{(g)} + Cl_{(g)}$
• B
  $NaCl_{(s)} \longrightarrow Na^{+}_{(g)} + Cl^{-}_{(g)}$
• C
  $Na_{(g)} + Cl_{(g)} \longrightarrow NaCl_{(s)}$
• D
  $Na^{+}_{(g)} + Cl^{-}_{(g)} \longrightarrow NaCl_{(s)}$