A coordination number can be determined by the usage of an atom towards a molecule from seeing how many numbers of atoms would have to be combined together in an atom.
Given the equation N=O/P, solve for P by multiplying the left and right by P/N:
N * P/N = O/P * P/N
P = O/N
A is correct because there is no reaction involved
The answer is Potassium Sulfide
