Of the following quantities which one has dimensions different from the remaining three ?

Question

\[\begin{array} {1 1}(a)\;energy\;per\;unit\;volume \\ (b)\;force\;per\;unit\;area\\ (c)\;product\;of\;voltage\;and\;charge\;per\;unit\;volume \\ (d)\;Angular\;momentum\;per\;unit\;mass \end{array}\]