ANS:E - all the above.

1. Exit gradient: The flow net provides information about the direction and magnitude of flow within a soil mass, allowing engineers to determine the exit gradient, which is the rate of change of hydraulic head along the exit gradient direction.
2. Seepage: Flow nets are particularly useful in analyzing seepage patterns through soil masses, such as embankments, dams, and retaining walls. They help visualize and quantify seepage flow paths and velocities.
3. Hydrostatic pressure: By analyzing the flow net, engineers can determine the hydrostatic pressure distribution within the soil mass, which is important for understanding the forces acting on retaining structures and assessing stability.
4. Seepage pressure: Seepage pressure refers to the pressure exerted by seeping water within a soil mass. Flow nets can aid in calculating seepage pressures at various points within the soil, providing valuable information for design and analysis.