Define electrochemical equivalent of a substance ?

Arrange the following energy units in order of increasing magnitude ?

$$\begin{gathered} \left(\mathrm{a}\right) \mathrm{Joule} \\ \left(\mathrm{b}\right) \mathrm{eV} \\ \left(\mathrm{c}\right)\mathrm{KWh} \\ \left(\mathrm{d}\right)\mathrm{erg} \end{gathered}$$