Particle-size distribution refers to the distribution of different sizes of particles in a soil sample. It is usually represented graphically as a particle-size distribution curve, which plots the percentage of particles of different sizes against their corresponding sizes.

a) Type of soil:
The particle-size distribution curve gives us information about the type of soil. Different types of soils have different particle-size distributions, which are determined by the geological processes that formed the soil. For example, sandy soils are characterized by a high percentage of coarse particles (sand), while clay soils have a higher percentage of fine particles (clay).

b) Properties of soil:
The particle-size distribution curve also provides insights into the properties of the soil. The size and distribution of particles affect various soil properties, including permeability, porosity, compaction, and shear strength. For instance, soils with a high percentage of fine particles (clay and silt) tend to have low permeability and high compressibility, while soils with a high percentage of coarse particles (sand and gravel) have higher permeability and lower compressibility.

c) All of the mentioned:
The particle-size distribution curve gives us information about both the type of soil and its properties. By analyzing the curve, we can determine the predominant particle size and the range of particle sizes present in the soil sample. This information helps in classifying the soil and understanding its behavior under different conditions.

Conclusion:
In conclusion, the particle-size distribution curve provides valuable information about the type of soil and its properties. It is an essential tool for soil classification and engineering design, as it helps in understanding how the soil will behave under different loading and environmental conditions. Therefore, the correct answer is option 'A' - the particle-size distribution curve gives us an idea about the type of soil.