Which of the following is not concentrated by electromagnetic separation?

Which of the following ores is concentrated by the froth flotation process?

Froth floatation process is used for the concentration of the ore of

The function of potassium ethyl xanthate in the froth floatation process is to make the ore

The correct statements regarding the froth floatation method in metallurgy are:
$I$. Used for the purification of sulphide ores
$II$. Used for the roasting of sulphide ores
$III$. It is based on the relative densities of gangue and ore particles
$IV$. It is based on the difference in the wetting properties of gangue and ore particles in frothing agent and water

Which among the following ores is concentrated by the froth flotation process?