Rank the following elements in order of their first ionization energy, from lowest to greatest: Ca, Ge, Br, Ga, Se.

• A. Ga < Ca < Ge < Se < Br
• B. Ca < Ga < Br < Ge < Se
• C. Se < Br < Ge < Ga < Ca
• D. Se < Ge < Br < Ga < Ca

Answer: (A)