Which One of the Following Sets of Ions Are Listed

Which one of the following sets of ions are listed in order of lowest to highest hydration energy?

A) H⁺ < Na⁺ < Mg²⁺
B) Mg²⁺ < Ca²⁺ < Ba²⁺
C) Mg²⁺ < Ba²⁺ < Ca²⁺
D) Ca²⁺ < K⁺ < Rb⁺
E) Rb⁺ < K⁺ < Ca²⁺