What are two things that can be done to maximize the chances of recovering parasites from a fecal smear?

Sedimentation - uses solutions of lower specific gravity than the organisms, which concentrated in the sediment. This technique is recommended for general diagnostic laboratories because it is easy to perform and less prone to technical errors.

Flotation - this technique uses solutions of higher specific gravity than the parasitic organisms so the organisms float and the debris sinks producing a cleaner material while the disadvantage is that walls of cysts and eggs collapse that may blocking its identification.

The right answer is c.sandstone.