Which supply type shows no responsiveness to price changes?

The concept of perfectly inelastic supply is characterized by a scenario where the quantity supplied remains constant regardless of changes in price. This means that no matter how much the price fluctuates, the quantity supplied does not change at all. This is often seen in cases where the good in question is a fixed resource or a unique item that cannot be produced in greater quantities no matter the market demand or price.

Perfectly inelastic supply is represented by a vertical supply curve on a graph, indicating that the quantity supplied is fixed and does not respond to price changes. An example could be rare collectibles or certain pieces of art, where the supply cannot be increased regardless of how high the price might go.

On the other hand, elastic supply indicates a situation where suppliers can easily increase quantity in response to price rises. Inelastic supply refers to a less dramatic change in quantity supplied when prices change, but there is still some responsiveness. Perfectly elastic supply means that suppliers are willing to offer any quantity at a specific price, and the quantity supplied would drop to zero if the price falls below this level.

Therefore, the nature of perfectly inelastic supply demonstrates a complete lack of responsiveness to price changes, making it the correct answer for this question.