The correct option is A Is based on the difference in wettability of different minerals
Froth floatation process used for the concentration of sulphide ores and it is a physical chemistry phenomenon based on the difference in wettability of different minerals. The general idea is that the ore particles (sulphide ore) are wetted by oil whereas the gangue particles are wetted by water. In other words, froth flotation is a process for selectively separating hydrophobic materials from hydrophilic.
Also, Sodium ethyl xanthate is used as a collector. The role of the collector is to make the slurry hydrophobic so it can froth out at the top. To encourage lasting and stable froth, frothers such as pine oil are added.
In the froth floatation process, the role of the depressants a mizture of sulphide ores by selectively preventing one ore from forming froth. For instance, to separate two sulphide ores ZnS and PbS, NaCN is used as a depressant. NaCN alllows PbS to froth up and rise by forming a soluble complex with ZnS.