ANS:C - 3.66

For fully developed laminar flow through a circular pipe with constant surface temperature, the Nusselt number (Nu) can be determined using the following correlation: =3.66Nu=3.66 This correlation is derived from the Graetz solution for laminar flow in a circular pipe with constant surface temperature boundary conditions. It represents the average Nusselt number for the entire length of the pipe under fully developed conditions. Therefore, the correct answer is 3.66.