Question

Let U - {q, r, s, t, u, v, w, x, y, z}

Answer 1

(A ∩ B)' is the complement of A ∩ B, or the set of all elements in the universal set U that do not belong to A ∩ B.

A ∩ B is the intersection of A and B, or the set of all elements common to both A and B.

We have

A = {q, s, u, w, y}

B = {q, s, y, z}

so that

A ∩ B = {q, s, y}

Then

(A ∩ B)' = {r, t, u, v, w, x, z}

which makes (c) the answer.