1. If $M=\left\{(x, y)|| \tan \pi y \mid+\sin ^{2} \pi x=0\right\}, N=\left\{(x, y) \mid x^{2}+y^{2} \leqslant 2\right\}$, then the number of elements in $M \cap N$ is
A. 4
B. 5
C. 8
D. 9
$M \cap N=\{(x, y) \mid x, y=-1,0,1\}, M \cap N$ has 9 elements. Therefore, the answer is $D$.