Which of the following is an endothermic reaction?

• A
  $N_{2(g)} + 3 H_{2(g)} \longrightarrow 2 NH_{3(g)} + 92 \ kJ$
• B
  $N_{2(g)} + O_{2(g)} + 180.8 \ kJ \longrightarrow 2 NO_{(g)}$
• C
  $H_{2(g)} + Cl_{2(g)} \longrightarrow 2 HCl_{(g)} + 184.6 \ kJ$
• D
  $C_{(graphite)} + 2 H_{2(g)} \longrightarrow CH_{4(g)} + 74.8 \ kJ$