Which of the following statements(s) is (are) true?
A. In process of the precipatation of silver from sodium dicyano argentate (I), the zinc acts as reducing agent as well as complexing agent.
B. In the process of roasting , the copper pyrites is converted inot a mixture of `Cu_(2)` & `FeS` which, in turn, are partially oxidised
C. Limonite , haemattien and magnesite are ores of iron.
D. Tin and lead both are extracted from their ores by self- ruduction.
