From the following data at $25^{\circ} C$,calculate the $\Delta_{r} H^0$ for the reaction $H_2O_{(g)} \rightarrow 2 H_{(g)} + O_{(g)}$:

$1/2 H_{2(g)} + 1/2 O_{2(g)} \rightarrow OH_{(g)}$	$\Delta H = 42.09 \ kJ \ mol^{-1}$
$H_{2(g)} + 1/2 O_{2(g)} \rightarrow H_2O_{(g)}$	$\Delta H = -242 \ kJ \ mol^{-1}$
$H_{2(g)} \rightarrow 2 H_{(g)}$	$\Delta H = 436 \ kJ \ mol^{-1}$
$O_{2(g)} \rightarrow 2 O_{(g)}$	$\Delta H = 496 \ kJ \ mol^{-1}$

• A
  $1174 \ kJ \ mol^{-1}$
• B
  $742 \ kJ \ mol^{-1}$
• C
  $926 \ kJ \ mol^{-1}$
• D
  $690 \ kJ \ mol^{-1}$