Question

The principle behind froth floatation is:

Answer 1

In froth floatation process, the desired mineral is rendered hydrophobic by the addition of a collector chemical. The hydrophobic grains of mineral-bearing ore rise to the surface, forming a foam or a scum (more properly called a froth). The froth is removed and the concentrated mineral is further refined.
Froth floatation process depends on the difference in wettability of particle by froath agents and not on other physical properties.
Hence option (a) is the correct.