Let \( A = \{(x,y) \in R \times R : |x + y| \ge 3\} \) and \( B = \{(x,y) \in R \times R : |x| + |y| \le 3\}. \) If \( C = \{(x,y) \in A \cap B : x = 0 \text{ or } y = 0\} \) then \(\displaystyle \sum_{(x,y)\in C} |x + y| \) is:
\( 15 \)
\( 18 \)
\( 24 \)
\( 12 \)