Sum of oxidation state (magnitude) and coordination number of cobalt in Na Co bpy Cl 4 is

2,2′-Bipyridine is an organic compound, This colorless solid is an important isomer of the bipyridine family. It is a bidentate chelating ligand, forming complexes with many transition metals.

There is one bidentate ligand and four monodentate ligand attached with Co metal ion. So, Coordination no. will be $=6$

This bpy ligand has no net charge. and chloride ion has -1 charge. So, Oxidation state of metal ion will be$=3$

Their sub will be =$6+3=9$