Which of the following pairs of metal and its ore is correct?

Azurite is an ore of

Identify the correct set of sulphide ores from the following.

Sulphide ion is a soft base and its ores are common for metals. Which of the following metals commonly occur as sulphide ores?
$(a)$ $Pb$ $(b)$ $Al$ $(c)$ $Ag$ $(d)$ $Mg$
Choose the correct answer from the options given below:

Which of the following are carbonate ores?
$I$. Magnetite
$II$. Kaolinite
$III$. Siderite
$IV$. Calamine

The common impurity present in bauxite is