Electron configuration, magnetism, and unpaired electrons

[Qube]

My answer key claims it's answer E. I don't think it's right; I think it's cobalt with three unpaired electrons. Not four. A 3d7 configuration, through the Aufbau principle, would fill two of the five d electron pairs completely and leave three half filled. This works mean it's also para magnetic, and it's obviously cobalt.

 

[K^2]

Well, yeah. If you have an odd number of electrons to be paired, you can't possibly have an even number of unpaired ones. You really don't have to even apply any rules of filling orbitals here. Number of paired electrons is even by definition. An odd number minus an even number is an odd number. So the answer is (2), of course.