a)

$\Omega =\left\{B1,B2,B3,C1,C2,N\right\}$

b)

$\Omega =\left\{\left(B1,B2\right),\left(B1,C1\right),\left(B1,C2\right),\left(B1,C3\right),\left(B2,C1\right),\left(B2,C2\right),\left(B2,C3\right),\left(C1,C2\right),\left(C1,C3\right),\left(C2,C3\right)\right\}$  

c)

$\Omega =\left\{\left(A,B,C\right),\left(A,B,D\right),\left(A,B,E\right),\left(A,C,D\right),\left(A,C,E\right),\left(A,D,E\right),\left(B,C,D\right),\left(B,C,E\right),\left(B,D,E\right),\left(C,D,E\right)\right\}$  

d)

$\Omega =\left\{\left(A,B,C,D,E\right),\left(A,B,C,D,F\right),\left(A,B,C,E,F\right),\left(A,B,D,E,F\right),\left(A,C,D,E,F\right),\left(B,C,D,E,F\right)\right\}$