Option 1 -> When inputs increase, output increases but at a slower rate (smaller proportion).
Option 2 -> When inputs increase, output increases at a faster rate (larger proportion).
Option 3 -> When inputs increase, output increases at the same rate (equal proportion).
Option 4 -> Not a standard term for returns to scale concept.
Hence, Decreasing Return to scale -> This occurs when all inputs are increased by a certain percentage, but output increases by a smaller percentage. For example, if labor and capital both increase by 100% (doubled), but output only increases by 50%, this represents decreasing returns to scale. This typically happens due to coordination problems, management inefficiencies, or resource constraints as operations scale up. -> correct