Consider the Born-Haber cycle for the formation of an ionic compound given below and identify the compound $Z$ formed.
$M_{(s)}$ $\xrightarrow{\Delta H_1} M_{(g)}$ $\xrightarrow{\Delta H_2} M^{+}_{(g)}$
$\frac{1}{2} X_{2(g)}$ $\xrightarrow{\Delta H_3} X_{(g)}$ $\xrightarrow{\Delta H_4} X^{-}_{(g)}$
$M^{+}_{(g)} + X^{-}_{(g)} \xrightarrow{\Delta H_5} Z$

• A
  $M^{+} X^{-}$
• B
  $M^{+} X^{-}_{(s)}$
• C
  $MX$
• D
  $M^{+} X^{-}_{(g)}$