In the following process/es `Delta H lt Delta U`
(A) `C(s) + O_(2)(g) rarr CO_(2)(g)`
(B) `CO(g)+(1)/(2)O_(2)(g) rarr CO_(2)(g)`
(C) `N_(2)(g)+3H_(2)(g) rarr 2NH_(3)(g)`
(D) `CaCO_(3)(s) rarr CaO(s) + CO_(2)(g)`