Steel contains

The major components of German Silver are:

Which of the following statement$(s)$ is/are incorrect?

Identify the correct statements from the following:
$I$. Brass is an alloy of copper and nickel
$II$. Bronze is an alloy of copper and zinc
$III$. German silver is an alloy of copper,zinc and nickel
$IV$. Brass is an alloy of copper and zinc

The correct statement$(s)$ related to the metal extraction processes is(are):
$(A)$ $A$ mixture of $PbS$ and $PbO$ undergoes self-reduction to produce $Pb$ and $SO_2$.
$(B)$ In the extraction process of copper from copper pyrites,silica is added to produce copper silicate.
$(C)$ Partial oxidation of sulphide ore of copper by roasting,followed by self-reduction produces blister copper.
$(D)$ In the cyanide process,zinc powder is utilized to precipitate gold from $Na[Au(CN)_2]$.