Out of the given ${\mathrm{CaC}}_2,{\mathrm{C}}_2{\mathrm{Cl}}_2$, ${\mathrm{C}}_2\mathrm{HCl},{\mathrm{C}}_2{\mathrm{H}}_2{\mathrm{Cl}}_2,{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}$ the number of molecules which contain two $\mathrm{\pi }$ bonds between the carbon atoms are

A single bond between two atoms is always considered as sigma bond.
A double bond between two atoms is always considered as one sigma and one pi bond

A triple bond between two atoms is always considered as one sigma bond and two pi bonds.

So according to the given structure ${\mathrm{CaC}}_2$ (Calcium carbide) has 1 sigma and $2\mathrm{pi}$ bonds

Hence, the correct option is option (D).