(A), (D)The important ore of tin is cassiterite (SnO2). Tin is extracted from cassiterite ore by carbon reduction method in a blast furnace.
\(SnO_2+ 2C \to Sn + 2CO\)
The product often contain traces of iron which is removed by blowing air through the melt to oxidize to FeO which then floats to the surface.
\(2Fe + O_2\to 2FeO\)