The Reaction 2NO(g)+ O₂(g) $\rightarrow$ 2NO₂(g)has $\Delta$ H_r $\degree$ = -114 KJMol ^{- 1}

The reaction 2NO(g) + O₂(g) $\rightarrow$ 2NO₂(g) has $\Delta$ H_r $\degree$ = -114 kJ.mol ^{- 1}.A possible mechanism for this reaction is 2NO(g) N₂O₂(g)
Rapid equilibrium,K
N₂O₂(g) + O₂(g) $\rightarrow$ 2NO₂(g)
Slow,k
If the activation energy for the reverse reaction is 225 kJ.mol ^{- 1},what is the activation energy for the forward reaction?

A) Because an intermediate is involved, the forward activation energy cannot be calculated with the given information.
B) 111 kJ.mol ^{- 1}
C) 339 kJ.mol ^{- 1}
D) 114 kJ.mol ^{- 1}
E) 55.5 kJ.mol ^{- 1}