1 Define the set operation: $A \otimes B=\{z \mid z=x y, x \in A, y \in B\}$. Let $A=\{2$, $0\}, B=\{0,8\}$, then the sum of all elements in the set $A \otimes B$ is ( ).
(A) 16
(B) 18
(C) 20
(D) 22
(1) The elements of the set $A \otimes B$: $z_{1}=2 \times 0=0, z_{2}=2 \times 8=16, z_{3}=0 \times$ $0=0, z_{4}=0 \times 8=0$, so the sum of all elements in the set $A \otimes B$ is 16. Therefore, the answer is $\mathrm{A}$.