Solution
Option 1 -> Economies of Sale is not a recognized economic concept and doesn't explain cost reduction with increased production volume.
Option 2 -> Economies of Production is a generic term but not the specific principle that describes declining costs as output increases.
Option 3 -> Economies of Scope refers to cost savings from producing multiple different products together, not from increasing volume of existing products.
Option 4 -> Economies of Scale occurs when increasing production volume leads to lower per-unit costs due to spreading fixed costs and operational efficiencies.
Hence, Option 4: Economies of Scale -> As the business grows and orders increase, fixed costs (machinery, rent, overhead) are distributed across more units, and the company benefits from bulk purchasing, better resource utilization, and improved efficiency. This results in declining production costs per unit, which is the fundamental principle of economies of scale. -> correct