\(\mathrm{V}_{\mathrm{D}}=0\, \mathrm{V}\)
\(\mathrm{V}_{\mathrm{E}}=0\, \mathrm{V}\)
\(\mathrm{v}_{\mathrm{B}}=-4 \,\mathrm{V}\)
\(\mathrm{V}_{\mathrm{A}}=5 \,\mathrm{V}\)
So, potential difference between the points
\(A\) and \(D\)
\(V_{A}-V_{D}=5\, \mathrm{V}\)