When in an economy, available resources are fully utilized at that point production of a combination of goods is known as .........

Option 1 -> Indifference Curve represents combinations of goods giving equal satisfaction to a consumer, not resource utilization.

Option 2 -> Isoquant shows combinations of inputs producing the same output level, not economy-wide resource allocation.

Option 3 -> Production Possibility Frontier shows maximum output combinations when all resources are fully and efficiently utilized.

Option 4 -> Production Possibility Set includes all feasible combinations, including inefficient ones inside the frontier.

Hence, Option 3: Production Possibility Frontier -> The PPF (also called Production Possibility Curve) represents the boundary showing maximum possible combinations of two goods an economy can produce when all available resources are fully and efficiently utilized. Points on the PPF indicate full employment and productive efficiency, while points inside represent underutilization of resources. -> correct