6. Given the origin $O$ and point $A(2,-2)$, $B$ is a point on the coordinate axis. If $\triangle A O B$ is an isosceles triangle, then the number of such points $B$ is ( ) .
(A) 4
(B) 5
(C) 6
(D) 8
6.D.

The points $B$ that satisfy the condition are located as follows: there are 3 on the positive direction of the $x$-axis, 3 on the negative direction of the $y$-axis, and 1 on each of the other two half-axes, making a total of 8 points.