A plane can be named using any three non-collinear points contained in the plane. Therefore, we are interested in all the points contained in plane M.
There are four points that lie in plane M: N, X, Y, and Z. However, X, Y, and Z are collinear, so we cannot use these to name the plane. Instead, we can use N and any two of the other three points. One example of a correct name for this plane is XNZ.
