Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."
Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...
Hopefully this has helped! :)
Answer : The magnetic moment of a single nickel atom is 
Explanation :
Formula used :

where,
= saturation magnetization = 
N = Avogadro's number = 
V = volume of nickel atom
= magnetic moment
First we have to calculate the volume of nickel atom.




Now we have to calculate the magnetic moment of a single nickel atom.



Therefore, the magnetic moment of a single nickel atom is 