Answer:
Demand decreases
Step-by-step explanation:
Substitute goods are products that can be used in place of each other. Goods are described as substitutes if a customer can use them interchangeably and get equal or almost the same satisfaction. Tea and coffee will be substitutes if a customer can consume either of them and be happy.
If the price of a substitute good declines, customers will prefer consuming it instead of the other product. The other product's demand will decrease due to a change in customer preferences as a result of a lower price.