Question

how do i calculate this from just an equation?
Which reaction shows that the enthalpy of formation of CS2 is Hf = 89.4 kJ/mol?

A. C(s) + 2S(s) CS2(l)
B. C(s) + 2S(s) CS2(l) + 89.4 kJ
C. C(s) + 2S(s) + 89.4 kJ CS2(l)
D. C(s) + 2S(s) + 89.4 kJ CS2(l) + 89.4 kJ