$\text{a)}A\cup B=B$  

$\text{b)}\left(A\cup B\right){}^{\prime }=B{}^{\prime }=\left\{x:x\in \mathbf{C}\wedge x\le -3\right\}$  

$\text{c)}A\cap B=A$  

$\text{d)}\left(A\cap B\right){}^{\prime }=A{}^{\prime }=\mathbf{C}-\left\{0,1,2,3,4,5\right\}$  

$\text{e)}A{}^{\prime }\cup B{}^{\prime }=A{}^{\prime }=\mathbf{C}-\left\{0,1,2,3,4,5\right\}$  

$\text{f)}A{}^{\prime }\cap B{}^{\prime }=B{}^{\prime }=\left\{x:x\in \mathbf{C}\wedge x\le -3\right\}$