Ellingham diagrams can be drawn for which of the following?

Which of the following reactions is $NOT$ entropy-driven with reference to extractive metallurgy? (unbalanced reactions)

Blister copper is ..........

The major components of German Silver are:

Thomas slag is used in

Among statements $(a)-(d),$ the correct ones are
$(a)$ Limestone is decomposed to $CaO$ during the extraction of iron from its oxides.
$(b)$ In the extraction of silver,silver is extracted as an anionic complex.
$(c)$ Nickel is purified by Mond's process.
$(d)$ $Zr$ and $Ti$ are purified by Van Arkel method.