The enthalpy of neutralisation of `NH_(4)OH` and `CH_(3)COOH` is -10.5 kcal `mol^(-1)` and enthalpy of neutralisation of `CH_(3)COOH` with strong base is -12.5 kcal `mol^(-1)`. The enthalpy of ionisation of `NH_(4)OH` will be
A. 4.0 kcal `mol^(-1)`
B. 3.0 kcal `mol^(-1)`
C. 2.0 kcal `mol^(-1)`
D. 3.2 kcal `mol^(-1)`
