A perfectly inelastic demand implies that buyers

a. decrease their purchases when the price rises.

b. purchase the same amount as before when the price rises or falls.

c. increase their purchases only slightly when the price falls.

d. respond substantially to an increase in price.

A perfectly inelastic demand implies that buyers purchase the same amount as before when the price rises or falls. Perfectly inelastic demand states that a consumer will still purchase a good or service regardless of a change in price. If there is a perfectly inelastic demand for an item, that means there is no substitute available for the item. If there is a substitute it will not be perfectly inelastic because someone could buy a different cheaper (cost) product in replacement.