Correct option is (B) 10
\(A B C D\) is a rectangle whose vertices are \(A(0,0), B(8,0),C(8,6)\) and \(D(0,6)\).
Length of diagonal \(A C\) is the distance between the points \((0,0)\) and \((8,6)\).
\(\therefore\) Length of diagonal \(AC =\sqrt{\left(x_{2}-x_{1}\right)^{2}+\left(y_{2}-y_{1}\right)^{2}}\)
\(=\sqrt{(8-0)^{2}+(6-0)^{2}}\)
\( =\sqrt{(8)^{2}+(6)^{2}} \)
\( =\sqrt{64+36}\)
\(=\sqrt{100}\)
\(=10\) units
