Which equation represents the reaction of nitrogen monoxide with hydrogen?
a) 2 NO + 2 H₂ -> N₂ + 2 H₂O
b) NO + 2 H₂ -> N₂ + 2 H₂O
c) 2 NO₂ + 2 H₂ -> N₂ + 2 H₂O
d) NO₂ + H₂ -> N₂ + 2 H₂O