When using Procedure B, how much wetting agent should be applied?

The correct choice revolves around the use of a wetting agent in hydrometer procedures, such as Procedure B, which is employed in particle size analysis of soils. The primary purpose of a wetting agent is to minimize surface tension in the water, allowing soil particles to disperse more effectively.

By applying enough wetting agent to produce a small amount of suds when agitated, you ensure that the agent is adequately functioning to break down any surface tension that may prevent the soil particles from fully interacting with the water. This is critical for accurate measurements, as it allows for a more representative sample to be analyzed without air bubbles hindering the results.

Other options do not align with the desired application of the wetting agent. For instance, completely dissolving the sample would not be appropriate because the aim is to maintain the integrity of the soil particles for measurement, rather than dissolving them. Using none or just a few drops would likely result in insufficient dispersion, leading to inaccurate readings. Thus, the requirement for a small amount of suds strikes the correct balance to facilitate proper testing.