A Solid Ball $\mathbf { A }$ Of Mass $m$ And Radius $r$

Multiple Choice

A solid ball $\mathbf { A }$ of mass $m$ and radius $r$ is placed at the top of a smooth, frictionless incline. Another solid ball $\mathbf { B }$ of equal mass and equal radius is placed at the top of a rough incline. Both inclines have the same height $h$ and the same angle. The balls are released. At the bottom, the ball that has the greater total kinetic energy is

A) ball A.
B) ball B.
C) Both have the same.
D) This cannot be determined unless $\mu$ of the rough incline is known.