(c)
$U = \left\{ x:x^{5} + 6x^{4} + 11x^{3} - 6x^{2} = 0 \right\} = \left\{ 0,\ 1,\ 2,\ 3 \right\}$
$A = \left\{ x:x^{2} - 5x + 6 = 0 \right\} = \{ 2,\ 3\}$
And $B = \left\{ x:x^{2} - 3x + 2 = 0 \right\} = \{ 2,\ 1\}$
$\therefore\ \ (A \cap B)^{'} = U - (A \cap B)$
$= \left\{ 0,\ 1,\ 2,\ 3 \right\} - \left\{ 2 \right\} = \{ 0,\ 1,\ 3\}$