Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is

ANS:C - mainly confined to a thin film of fluid near the surface.

The bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it is mainly confined to a thin film of fluid near the surface. This thin film of fluid near the surface, known as the boundary layer, experiences the most significant temperature gradient and thus contributes the most to the convective heat transfer resistance. As a result, the convective heat transfer resistance is primarily concentrated within this thin film of fluid. Therefore, the correct option is: "mainly confined to a thin film of fluid near the surface."