c
According to \(M.O.T.\) electronic configuration of \(\mathrm{C}_{2}\) molecule is

\(\sigma 1 \mathrm{s}^{2}<\sigma^{*} 1 \mathrm{s}^{2}<\sigma 2 \mathrm{s}^{2}<\sigma^{*} 2 \mathrm{s}^{2}<\pi_{2} \mathrm{p}_{\mathrm{x}}^{2}=\pi_{2} \mathrm{p}_{\mathrm{y}}^{2}\)

so, \(\mathrm{C}_{2}\) molecule contain only \(\pi\) bond