A turbulent boundary layer remains attached over a longer distance on the upper surface of an airfoil than does a laminar boundary layer, because

• A. the turbulent boundary layer is more energetic and hence can overcome the adverse pressure gradient better
• B. the laminar boundary layer develops more skin friction and hence slows down more rapidly
• C. turbulence causes the effective coefficient of viscosity to reduce, resulting in less loss of momentum in the boundary layer
• D. the turbulent boundary layer is thicker, hence the velocity gradients in it are smaller, therefore viscous losses are less