What is the coordination number of each type of ions in a rock salt type crystal structure ?

Question

$\begin{array}{1 1}(a) Na^+ = 5 , Cl^- = 4 \\(b) Na^+ = 5 , Cl^- = -4\\(c)\;Na^+ = 5 , Cl^- =6\\(d)\; Na^+ = 6 , Cl^- = 6\end{array}$