At `300K` , the standard enthalpies of formation of `C_(6)H_(5)COOH_((s),CO_(2(g))` and `H_(2)O_((l))` are `-408,-393` and `-286kJ mol^(-1)` respectively. Calculate the heat of combustion of benzoic acid at
`(i)` constant pressure,
`(ii)` constant volume. `(R=8.31J mol^(-1)K^(-1))`
A. `+3201` kJ
B. `+3199.75` kJ
C. `-3201` kJ
D. `-3199.75` kJ