The correct option is A Solvay process Sodium carbonate is a salt of carbonic acid with chemical formula$$Na_2CO_3$$. It is also known as Soda crystals, soda ash, washing soda. It is manufactured by the Solvay process.
Sodium carbonate is prepared by passing carbon dioxide through ammonia that gives ammonium carbonate. Subsequently, ammonium carbonate is converted to ammonium hydrogen carbonate that reacts with sodium chloride to precipitate out sodium hydrogen carbonate. Sodium hydrogen carbonate later forms sodium carbonate.