Concept:Complementary goods are products used together, so demand for one increases when demand for the other increases.
Explanation:A torch and batteries are complementary goods because a torch requires batteries to work.
If the demand for torches rises, the demand for batteries also rises.
This mutual relationship is known as complementary demand.
It is not competitive demand, because the goods are not substitutes.
It is not composite demand, because batteries are not used for several distinct purposes here.
It is not derived demand, because batteries are not a factor of production used to make torches; they are consumed alongside torches.
Answer:C. complementary demand