Final answer:
The typical angle of repose is around 35%, which describes the steepest stable slope angle for loose materials.
Step-by-step explanation:
The angle of repose is the steepest angle at which a pile of unconsolidated material, such as soil, sediment, or other loose granular elements, will remain stable without any of the material sliding down.
The typical angle of repose is around 35% (Option C), but this can vary with different materials and moisture conditions.
This measurement is important in fields like geology, engineering, and construction.