Calculate the Br-Br Bond Enthalpy Given the Standard Enthalpies of Formation

Calculate the Br-Br bond enthalpy given the standard enthalpies of formation for Br₂(g) and Br(g) ,30.7 and 112 kJ.mol ^{- 1},respectively.

A) 193 kJ.mol ^{- 1}
B) 255 kJ.mol ^{- 1}
C) 143 kJ.mol ^{- 1}
D) 81 kJ.mol ^{- 1}
E) 30.7 kJ.mol ^{- 1}