The spin-only magnetic moment of $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ (rounded off to one decimal place) is ____ BM.
Answer
Answer (as printed): 3.9
The options are missing from the source scan for this question, so there is nothing here for this letter to point at. The letter is what the book printed.