A hypothetical AX type ceramic material is known to have a density of 2.10g/cm3 and a unit cell of cubic symmetry with a cell edge length of 0.57nm. The atomic weights of the A and X elements are 28.5 and 30.0g/mol, respectively. On the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende?