Steel slag can be the material for which of the following? 1. Construction of base road 2. Improvement of agricultural soil 3. Production of cement Select the correct answer using the code given below:

1. Statement 1 is correct. Steel slag possesses high strength, hardness, and good drainage properties, making it a suitable aggregate material for the construction of base and sub-base layers in roads. 2. Statement 2 is correct. Steel slag contains calcium silicate and other minerals that can help neutralize acidic soils (liming effect) and provide essential nutrients like calcium, magnesium, and silicon. Its use can lead to the improvement of agricultural soil structure and fertility. 3. Statement 3 is correct. Due to its chemical composition (rich in calcium, silicon, aluminum, and iron oxides) and cementitious properties, steel slag can be used as a raw material or supplementary cementitious material in the production of cement and concrete, partially replacing clinker or aggregates. 4. Therefore, steel slag can be used for all three mentioned purposes.