Q. Pick out the wrong statement.

• (A) Addition of methane to the furnace atmosphere reduces decarburising by hydrogen
• (B) Nitrogen in presence of steam decar-burises high carbon steel, whereas hydrocarbon gases carburise the surface of steel at annealing temperatures
• (C) Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation with increase in surface hardness
• (D) None of these