In the following molecule,
Hybridisation of Carbon a, b, and c respectively are :

Solution

Chemistry ma’am · 3 steps

Count the σ bonds on each labelled carbon: 4 means sp³, 3 means sp², 2 means sp.

1. The counting rule. For a carbon, hybridisation follows the number of atoms it is bonded to. Four σ bonds gives sp³, three σ bonds plus one π bond gives sp², and two σ bonds plus two π bonds gives sp.

   Carbon	Bonded to	σ bonds	π bonds	Hybridisation
   a (CH₃)	3 H and 1 C	4	0	sp³
   b (alkene C)	1 C, 1 H, 1 O	3	1 (the C=C)	sp²
   c (ring C)	1 O and 2 ring C	3	1 (in the ring)	sp²

2. Ignore the oxygen. The oxygen next to b and c only supplies one σ bond to each. Its lone pairs may be in resonance with the double bond and the ring, but resonance does not change the carbon's hybridisation.
3. So. Carbons a, b and c are sp³, sp² and sp², which is option (a).

The idea to keep. For any carbon, just count its neighbours: 4 neighbours is sp³, 3 is sp², 2 is sp. Every benzene ring carbon is sp², whatever group sits on it.

Answer from the NTA final answer key. Solution by PrepWiser.