Question

each currency has a changing value relative to other currencies. this is referred to as a currency’s
○ exchange rate
○ currency value
○ exchange value
○ currency rate

Explanation:

The question is about the term for a currency's changing value relative to other currencies. By definition, the exchange rate is the rate at which one currency can be exchanged for another, representing the relative value change. "Currency value" is too general, "exchange value" is not the standard term, and "currency rate" is not a recognized term for this concept.

Answer:

A. exchange rate