The coordination number of central metal atom in a complex is determined by

Question

$\begin{array}{1 1}(a)\;\text{The no of ligands around a metal ion bonded by }\sigma\;\text{bonds}\\(b)\;\text{The no of only anionic ligands bounded by the metal ion}\\(c)\;\text{The no of ligands around a metal ion bounded by }\sigma\;\text{bonds}\;\pi\;\text{bonds both}\\(d)\;\text{The no of ligands around a metal ion bounded by }\;\pi\;\text{bonds}\end{array}$