Which of these laws define the dimensionless quantities

Which of these laws define the dimensionless quantities u^+ and y^+?

A. Velocity-defect law B. Log-law C. Newton’s law of viscosity D. Law of the wall

Correct option is D. Law of the wall

The law of the wall is the relationship between the mean flow velocity and the distance from the wall derived using dimensional analysis. This gives the relationship between two important dimensionless quantities u^+ and y^+.