In the following molecule,Hybridisation of carbon \( a \), \( b \) and \( c \) respectively are:
\( \mathrm{sp}^3 \), \( \mathrm{sp} \), \( \mathrm{sp} \)
\( \mathrm{sp}^3 \), \( \mathrm{sp} \), \( \mathrm{sp}^2 \)
\( \mathrm{sp}^3 \), \( \mathrm{sp}^2 \), \( \mathrm{sp} \)
\( \mathrm{sp}^3 \), \( \mathrm{sp}^2 \), \( \mathrm{sp}^2 \)