For steady, fully developed flow inside a straight pipe of diameter D, neglecting gravity effects, the pressure drop Δp over a length L and the wall shear stress τw are related by A. τw = ΔpD/4L B. τw = ΔpD^2/4L^2 C. τw = ΔpD/2L D. τw = 4ΔpL/DAns: