Final answer:
When the prices of substitute resources decrease, the demand for a given resource decreases.
Step-by-step explanation:
The correct answer is C) The demand for a given resource decreases.
When the prices of substitute resources decrease, people tend to substitute towards the cheaper resource and reduce their consumption of the given resource.
This is known as the substitution effect. For example, if the price of plane tickets decreases, people may choose to fly instead of taking the train, leading to a decrease in the demand for train tickets.
Therefore, when the prices of substitute resources decrease, the demand for a given resource generally decreases.