The velocity profile of a fully developed laminar flow in a straight circular pipe, as shown in the figure, is given by the expression.

Where dp/dx is a constant.

The average velocity of the fluid in the pipe is A. −R^2/8μ (dp/dx) B. R^2/4μ (dp/dx) C. −R^2/2μ (dp/dx) D. −R^2/μ (dp/dx)