8.46 In the Cartesian coordinate system, there is a circular arc with a central angle of $30^{\circ}$, and its center is on the $y$-axis. The number of intersection points between this arc and the curve $y=\sin x$ is
(A) 0 or 1.
(B) 0 or 1 or 2.
(C) Any natural number.
(D) 0 or any natural number.
（2nd "Hope Cup" National Mathematics Invitational Competition, 1991）
［Solution］Since the center of the circle is on the $y$-axis, but its radius is not limited, thus:
When the radius of the circle is sufficiently small, and the center of the circle is sufficiently far from the origin, the circular arc has no intersection points with the curve $y=$ $\sin x$;

Also, when the radius of the circle is sufficiently large, and the center of the circle is sufficiently far from the origin, the two can have a finite or infinite number of intersection points.
Therefore, the correct choice is $(D)$.