a
Energy density  = \([ {\frac{{workd\,done}}{{volume}}} ] = \frac{{ML{T^{ - 2}} \cdot L}}{{{L^3}}} = [ {M{L^{ - 1}}{T^{ - 2}}}\)
 Young's  modulus = \(\left[ Y \right] = \left[ {\frac{{Force}}{{Area}}} \right] \times \frac{{\left[ l \right]}}{{\left[ {\Delta l} \right]}}\)
\(= \frac{{ML{T^{ - 2}}}}{{{L^2}}}\, \cdot \frac{L}{L} = \left[ {M{L^{ - 1}}{T^{ - 2}}} \right]\)
The dimensionsof \(1\) and \(4\) are the same.