The standard enthalpy of formation of `NH_(3)` is `-46.0KJ mol^(-1)` . If the enthalpy of formation of `H_(2)` from its atoms is `-436KJ mol^(-1)` and that of `N_(2)` is `-712KJ mol^(-1)` , the average bond enthalpy of `N-H` bond in `NH_(3)` is
A. `+1056kJ" "mol^(-1)`
B. `-1102kJ" "mol^(-1)`
C. `-964kJ" "mol^(-1)`
D. `+352kJ" "mol^(-1)`