ANS:C - high

For high Prandtl number values, the heat conduction will be negligible in the buffer zone. The Prandtl number (Pr) is the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity. It indicates the relative importance of momentum diffusion to thermal diffusion in a fluid. When the Prandtl number is high, it means that thermal diffusivity is relatively low compared to momentum diffusivity. In other words, the fluid has a high capacity to resist changes in temperature compared to its ability to transfer momentum. In such cases, the rate of thermal diffusion is significantly lower than the rate of momentum diffusion. Therefore, in the buffer zone (the region between the boundary layer and the main flow), where momentum diffusion dominates, the heat conduction will be negligible. Hence, for high Prandtl number values, the heat conduction will be negligible in the buffer zone.