Which of the following three sets consist of atoms or ions with the same electron configuration in the ground state? I. O (2-), Ne, and Mg (2+) II. Ni, Cu+, Zn 2+ III. Hg, Tl+, and Pb (2+) a. all but (II) b. all but (I) c. all three sets d. only (I) Is it all but ii. because Cu loses its 4s shell? Thanks.