Answer: U, W, Z and Y
Explanation:
4 points are not coplanar if there does not exist any plane that contains the 4 points.
So, a plane is formed by a line and one point outside of it.
Then, we want to select the last point in such a way that it lies outside of the plane generated by the first 3 points selected.
For example:
If first we select Point U and Point W, we will have a line, as shown in the image.
Now we can select the Point Z, that is outside the line, and now we have the plane M that you can see in the image.
Now we need to select a point that is not in the plane, the only two options are Point X and Point Y, we can select any of those two, let's take the Point Y.
So, here we have that:
Points U, W, Z and Y are not coplanar.