The fact that a resource used in the production of the good is available only in limited quantities.
Answer: Option B.
Step-by-step explanation:
The long run supply curve in an industry in which development doesn't change input costs (a steady cost industry) is a horizontal line. The since quite a while ago run supply bend for an industry in which creation costs increment as yield rises (an expanding cost industry) is upward inclining.
In the long run aggregate supply curve is consummately vertical, mirroring financial analysts' conviction that adjustments in total interest just purpose a transitory change in an economy's absolute yield. The since a long time ago run total stockpile bend can be moved, when the elements of creation change in amount.