The number and type of bonds in $\;C_{2}^{2-}\;$ ion in $\;CaC_{2}\;$ are :

Question

(a) one $\;\sigma\;$ bond and one $\;\pi -\;$ bond\[\](b) one $\;\sigma\;$ bond and two $\;\pi -\;$ bond\[\](c) two $\;\sigma\;$ bond and two $\;\pi -\;$ bond \[\](d) two $\;\sigma\;$ bond and one $\;\pi -\;$ bond