[TexasGator]

” A sedan has an a-pillar behind the front doors.”

B

[Dr. Sivana]

I apologize for the mistype. Obviously, you got the idea. The roadsters and convertibles are missing the a-pillar.

[Mr Rogers]

In picture form, to help folks visualize:

"Alternatively, a coupé is often distinguished from a two-door sedan by the lack of a B pillar to support the roof. Sedans have an A pillar forward at the windscreen, a B pillar aft of the door, and a C pillar defining the aftermost roof support at the rear window."

https://en.wikipedia.org/wiki/Coup%C3%A9