How is the hybridization of carbon in an organic compound determined based on its structure? Explain.

(N/A) $sp^{3}$ hybridized carbon: If the carbon atom is bonded to four other atoms by single bonds (all $\sigma$-bonds).
$sp^{2}$ hybridized carbon: If the carbon atom is bonded to three other atoms and has one $\pi$-bond.
$sp$ hybridized carbon: If the carbon atom is bonded to two other atoms and has two $\pi$-bonds.