Which of the Following Reactions Is the Most Likely to Give

Multiple Choice

Which of the following reactions is the most likely to give off heat?

A) Al(s) $\rightarrow$ Al(g)
B) Al(g) $\rightarrow$ Al³⁺(g) + 3 e^-
C) Al^-(g) $\rightarrow$ Al(g) + e^-
D) 2 Al(s) + conc. HNO₃(aq) $\rightarrow$ 2 Al³⁺(aq) + 3 H₂(g)
E) all these reactions should give off energy.