ANS:D - All the above.

1. The permeability of the coarse-grained soils may be reduced by grouting: This statement is generally incorrect. Grouting is typically used to improve permeability in soils or rock formations, not to reduce it. By injecting grout into the pore spaces of coarse-grained soils, voids can be filled, and the permeability can be reduced, allowing for improved stability and reduced water flow.
2. The process of injecting fluids (i.e., grouts) into the pore space of the soil is called grouting: This statement is accurate. Grouting is indeed the process of injecting fluids, known as grouts, into the pore spaces of soil or rock formations. Grouting can serve various purposes, including improving stability, sealing voids, reducing permeability, and strengthening the ground.
3. The grouting increases the soil strength: This statement is not always accurate. The effect of grouting on soil strength can vary depending on several factors, including the type of grout used, the injection method, and the soil conditions. While grouting can improve the stability and integrity of soil or rock formations in some cases, it does not universally increase soil strength. The effectiveness of grouting in enhancing soil strength depends on the specific project requirements and the characteristics of the soil.