If three sides are the sides of a right triangle, then the greatest side is the hypotenuse and the lengths should satisfy the Pyhtagorean Theorem:
[tex]a^2+b^2=c^2[/tex]Notice that:
[tex]\begin{gathered} 4^2+8^2=16+64=80 \\ 10^2=100 \end{gathered}[/tex]Since:
[tex]4^2+8^2\ne10^2[/tex]Then, 4, 8 and 10 cannot be the sides of a right triangle.
Therefore, the answer is:
[tex]C[/tex]
