To determine if the statement is true or false, we need to verify if the given expression \((A \cap B)^{\prime} = A^{\prime} \cup B^{\prime}\) is correct. This is a known result from set theory called De Morgan's Law, which states that the complement of the intersection of two sets is the union of their complements. Therefore, the statement is true.
Let \( A = \{1, 2, 3\} \) and \( B = \{3, 4, 5\} \).
The intersection \( A \cap B = \{3\} \). The complement of the intersection, denoted as \( (A \cap B)^{\prime} \), is calculated as:
\[
(A \cap B)^{\prime} = \{1, 2, 4, 5\}
\]
The complement of set \( A \), denoted as \( A^{\prime} \), is:
\[
A^{\prime} = \{4, 5\}
\]
The complement of set \( B \), denoted as \( B^{\prime} \), is:
\[
B^{\prime} = \{1, 2\}
\]
The union of the complements \( A^{\prime} \cup B^{\prime} \) is:
\[
A^{\prime} \cup B^{\prime} = \{1, 2\} \cup \{4, 5\} = \{1, 2, 4, 5\}
\]
We find that:
\[
(A \cap B)^{\prime} = \{1, 2, 4, 5\} \quad \text{and} \quad A^{\prime} \cup B^{\prime} = \{1, 2, 4, 5\}
\]
Since both expressions are equal, we conclude that the statement \( (A \cap B)^{\prime} = A^{\prime} \cup B^{\prime} \) is true.
The answer is \( \boxed{C} \).