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 same time. The ball that reaches the bottom first is

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