Which test is conducted on cohesionless soil to assess the distribution of grain size?

The correct answer is the Sieve Analysis test, which is specifically designed to determine the grain size distribution of cohesionless soils, such as sands and gravels. During this process, soil samples are passed through a series of sieves with varying mesh sizes, allowing for the separation of soil particles based on their size. The results provide valuable information regarding the soil's composition, which is essential for various engineering applications, such as determining soil stability and behavior under load.

In contrast, the Atterberg Limits are used to classify fine-grained soils based on their plasticity characteristics and do not focus on grain size distribution. The Proctor Test is primarily concerned with determining the optimum moisture content at which a soil achieves its maximum dry density, and it does not provide detail on grain sizes. The Moisture Content Test measures the amount of water present in soil but does not provide information about the soil's particle size distribution. Each of these tests serves a different purpose and is vital in geotechnical engineering, but for assessing grain size distribution in cohesionless soils, Sieve Analysis is the appropriate choice.