Concept:Substitute goods are those that can be used in place of each other to satisfy the same want.
Explanation:When the price of commodity
X rises, it becomes more expensive for consumers.
Consumers then look for an alternative that gives similar satisfaction at a lower cost.
Because they move to commodity
Y, the demand for
Y increases.
A direct relationship exists: a rise in the price of one good causes an increase in the demand for the other.
Therefore,
X and
Y serve the same purpose and are not used together.
Goods used together are complements, not substitutes.
Thus,
X and
Y are substitutes.
Answer:A. substitutes