Concept:Competitive demand describes goods that serve as substitutes for each other in satisfying similar wants.
Explanation:When two goods are in competitive demand, they can replace one another.
If the demand for one commodity rises, consumers tend to buy more of it and less of the alternative.
As a result, the demand for the substitute commodity falls.
This relationship does not apply to complementary goods, because an increase in one complementary good raises, rather than lowers, the demand for the other.
Therefore, the correct condition is competitive demand.
Answer:D. in competitive demand