The number and type of bonds between two carbon atoms in $CaC_2$ are

Question

$\begin{array}{1 1} \text{One $\sigma$ and one $\pi$ bonds} \\ \text{One $\sigma$ and two $\pi$ bonds} \\ \text{One $\sigma$ and one and half $\pi$ bonds} \\ \text{One $\sigma$ bonds} \end{array}$