What is the standard enthalpy of formation of MgCO3( s )?

What is the standard enthalpy of formation of MgCO3(s)?
                                      MgO(s) + CO2(g)  → MgCO3(s);          ΔH° = -100.7 kJ
 SubstanceΔH°f (kJ/mol)
MgO(s)-601.6
CO2(g)-393.5
A. 107.4 kJ
B. -308.8 kJ
C. -894.4 kJ
D. -1095.8 kJ
E. 894.4 kJ