Option A is Corre
A is Correct: Modern chemistry defines organic compounds as hydrocarbons and their derivatives.
Option B Explained
B is incorrect and the outdated definition. This definition was used when no compound was synthesized in laboratory.
Option C Explained
Option C is incorrect. Carbonates and oxides of carbon contain carbon yet inorganic.
Option D Explained
This ignores the lone pair completely. The lone pair changes both the electron-domain count and the visible shape.