Determining unpaired electrons in transition metal ions

Steps:

• Recall atomic numbers: Cu (29), Mn (25), V (23).
• Write electron configurations for neutral atoms and remove electrons for ions.
• Determine d-electron count and unpaired electrons assuming high-spin octahedral (free ion approximation).
• Compare to question: identify ions with ≥1 unpaired electron.

Not enough information: Option D is missing, making the full set of choices ambiguous.

Final answer: Not enough information.