Which of the following scenarios best exemplifies perfectly inelastic demand?

Perfectly inelastic demand means that consumers will buy the same amount of a product no matter what the price is. This usually happens with essential goods that have no substitutes, like life-saving medications. For example, if a person needs insulin to manage diabetes, they will buy it even if the price significantly increases, because their health depends on it. In this case, the quantity demanded does not change regardless of price fluctuations, showing that the demand is perfectly inelastic. This concept helps us understand how some products are non-negotiable for consumers, regardless of cost.