Based on The $\Delta$ H°_f Data Given, Which of the Following Compounds Is the Following

Based on the $\Delta$ H°_f data given, which of the following compounds is the most unstable?

A) SrO(s) , -592.0 kJ/mol
B) CsBr(s) , -396 kJ/mol
C) CaF₂(s) , -1215 kJ/mol
D) NaI(s) , -288 kJ/mol
E) KF(s) , -568.6 kJ/mol