Which factor relates to the price of substitute goods affecting demand?

The relationship between the price of substitute goods and demand is fundamentally linked to the availability of alternatives. When the price of a substitute good rises, consumers may shift their preferences towards the alternative that is now relatively cheaper, leading to an increase in demand for that substitute. Conversely, if the price of a substitute good falls, the demand for the original good may decrease as consumers opt for the less expensive option. This dynamic illustrates how the presence of alternatives impacts consumer choices and overall market demand.

In this context, other factors like incomes, complementarity, and consumer preferences do play essential roles in shaping demand. However, they do not directly address how the pricing of substitute goods influences the demand for one another as clearly as the availability of alternatives.