Demand curves assume which of the following?

The correct answer is based on the fundamental principle of demand curves in economics. Demand curves are graphical representations that illustrate how the quantity demanded of a good or service varies with its price. The assumption that "Price is the only factor affecting demand" aligns with the ceteris paribus condition, which means "all other things being equal."

This assumption simplifies the analysis by focusing solely on the relationship between price and quantity demanded, while keeping other factors constant, such as consumer income, preferences, and the prices of related goods. In reality, many factors can influence demand, but the demand curve specifically illustrates the change in quantity demanded as a direct result of price fluctuations.

In this context, while other factors like consumer preferences or external variables may affect demand in a broader sense, the demand curve itself is a tool designed to isolate the price effect, illustrating the basic economic principle of how price changes impact consumer buying behavior.