The correct way to use percentages in this context is:

A. Percentages can be used to describe a change in something. For example, the cost of milk rose 5% within the past month.

This illustrates how percentages can describe the extent of a change over time, which is another common use of percentages.

Would you like further clarification or have additional questions?

Here are five related questions for further exploration:

1. How do you calculate the percentage change between two values?
2. What real-world situations often involve percentage changes?
3. How does a percentage increase differ from a percentage decrease?
4. How can percentage changes affect financial decision-making?
5. What are the potential pitfalls of misinterpreting percentage changes?

Tip: When discussing percentage changes, remember that a small percentage can still represent a significant impact depending on the context, such as in financial markets.