In the given Venn diagram, the shaded area represents the region outside of both sets \( A \) and \( B \), which corresponds to the complement of the union of \( A \) and \( B \). In set notation, this is written as:
\[
A' \cap B' \quad \text{(the region outside both \( A \) and \( B \))}
\]
Thus, the correct answer is \( A' \cap B' \), which represents the region that is outside both sets \( A \) and \( B \).