An object possesses a mirror plane symmetry element, ("sigma"), if the object can be reflected through a defined plane and the object remains indistinguishable from the original. For instance, if we define a mirror plane that exists in the xz plane in the coordinate system below, then the point (x,y,z) becomes (x,y,z). Which of the following objects possess an that exists in the xz plane (a.k.a. xz)? (Note that A-D are "flat", nearly 2- XZ dimensional objects derived from square planar geometries, whereas E-G are 3- dimensional objects) Z A) B) C) D) E) + Z y F) + G)