Option C: a true solution will not separate in a centrifuge.
A solution is said to be a true solution if the solute particles form homogeneous mixture with the solvent. In a homogeneous mixture, the size of the particle of solute is less than 1 nm, can not be seen from naked ice. In such solutions, the solute particles completely dissolves in solvent in all proportions and cannot settle down at bottom if kept at rest for some time.
As complete dissolution of solute takes place, there is no cloudy appearance in the true solution also, once the solution is formed solute and solvent particles can not be separated with simple processes such as heating, boiling and centrifugation.
For example, solution of sugar and water, sugar particles completely dissolve in water to form homogeneous mixture or true solution.
Therefore, a true solution will not separate in a centrifuge.