Static friction between two surfaces

If the static friction between two surface P and Q is measured to be 50 N, then the sliding friction between these two surface is most likely to be :

If the static friction between two surface X and Y is found to be 20 N, then the rolling between these two surfaces should most likely be :

The limiting friction between two surfaces depends

What is the angle of friction, if the coefficient of friction between two surfaces is 0.25 ?

The limiting friction between two surface does not depend

Consider the following statements A) The coefficient of friction between two surfaces will increase if the surfaces are made rough. B) rolling friction is more than sliding friction