If universal set ξ = {x : x ∈ W, x < 5} and set A = {1, 3}, then complement of set A is equal to :

1. {0, 2, 4, 5}

2. {0, 2, 4}

3. ϕ

4. {2, 4}

If universal set = N, the set of natural numbers, set A = {multiples of 3 less than or equal to 20}
and
Set B = {multiples of 4 less then or equal to 20}, then A - B is equal to :

1. {3, 6, 9, 15, 18}

2. {4, 8, 16, 20}

3. {0}

4. {12}

Find all the subsets of B = {a, b, c} .

Find all the subsets of C = {x : x ∈ W, x ≤ 2} .