Explanation

Under the green guidelines of the Pradhan Mantri Gram Sadak Yojana (PMGSY), eco-friendly materials and waste-utilization methods are prioritized to lower emissions and carbon footprints:

– 1. Copper slag (Preferred): Replaces mined natural aggregates and river sand in sub-base layers, reducing environmental destruction and industrial waste.
– 2. Cold mix asphalt technology (Preferred): Produced by blending emulsified bitumen with unheated aggregates at ambient temperature, eliminating toxic hydrocarbon fumes, cutting fuel combustion, and reducing energy expenditure.
– 3. Geotextiles (Preferred): Permeable synthetic or natural jute/coir fabrics reinforce soil sub-grades, control sub-surface erosion, and increase pavement design life sustainably.
– 4. Hot mix asphalt (Not preferred for green roads): Involves burning heavy fossil fuels to heat aggregates and bitumen to over 150-160 degrees Celsius, generating significant greenhouse gas emissions.
– 5. Portland cement (Not preferred for carbon reduction): Traditional Portland cement manufacturing is highly carbon-intensive, releasing large volumes of carbon dioxide.

Hence, technologies 1, 2, and 3 are preferred — Option A.