From the following, the correct statements about the role of substances added in the froth flotation process are:

a. Collectors enhance the non-wettability of the mineral particles.
b. Collectors enhance the wettability of gangue particles.
c. By using depressants in the process, two sulphide ores can be separated.
d. Froth stabilisers decrease the wettability of gangue.


1. a and b
2. b and c
3. c and d
4. a and c