ANS:D - all the above.

1. Excess pore pressure: Excess pore pressure is the additional pressure that develops within the pore water of a soil mass when it is subjected to external loads or changes in stress conditions. When a soil is loaded, the water initially trapped in the pore spaces experiences an increase in pressure due to the applied load. This excess pore pressure can influence various soil behaviors such as consolidation, settlement, and stability.
2. Excess hydrostatic pressure: This term is not commonly used in geotechnical engineering. However, it could potentially refer to the additional pressure beyond the hydrostatic pressure that exists within the pore water due to external loading. In geotechnical contexts, excess pore pressure is the more commonly used term to describe this phenomenon.
3. Hydrodynamic pressure: Hydrodynamic pressure typically refers to the pressure exerted by moving fluids, such as water, due to their motion. In geotechnical engineering, hydrodynamic pressure may be relevant in scenarios involving water flow, such as seepage through soil masses or hydraulic structures. It's less directly related to the phenomenon of excess pore pressure due to loading.