(a) Force of friction is zero and negligible for ball 1 & 3 respectively, so energy is conserved for balls 1 and 3.
(b) Ball 1 acquired rotational energy, ball 2 loses energy by friction. They cannot cross at C. ball 3 can cross over.
(c) Ball 3 have negligible friction & crosses C so ball cannot reach at A.
Ball 1, 2 turn back before reaching C. because of loss energy, ball 2 cannot reach back to A. ball 1 has rotational motion in “wrong: sense when it reaches B, It cannot roll back to A, because of kinetic friction.