The number and type of bonds in $C_2^{2-}$ ion in $CaC_2$ are

• A
  One $\sigma$ bond and one $\pi$ bond
• B
  One $\sigma$ bond and two $\pi$ bonds
• C
  Two $\sigma$ bonds and two $\pi$ bonds
• D
  Two $\sigma$ bonds and one $\pi$ bond