CaO+CO2 , In Blast furnace } lime stone (b) Ag form cyanide complex [Ag(CN) 2]− during cyaride process Ag∕Ag2S+CN⊖→[Ag(CN)2]− (c) Ni is purified by mond's process (d) Zr and Ti are purified by van arkel method All (a), (b), (c), (d) are correct statements Thus correct option is (4)