The demand for torch and batteries is an example of

Step 1: Analyze the question Torch and batteries are used together. A torch is useless without batteries, and batteries are needed to make the torch work. The question asks what type of demand this relationship represents.

Step 2: Explain the concepts

• Competitive demand: demand for goods that are substitutes. Buying one means buying less of the other (e.g., Coke and Pepsi).
• Composite demand: demand for a good that has several uses (e.g., demand for steel, which is used for cars, buildings and machines).
• Complementary demand (joint demand): demand for goods that are used together, so demand for one rises or falls with demand for the other (e.g., car and fuel, bread and butter, torch and batteries).
• Derived demand: demand for a good because it is needed to produce another good (e.g., demand for cocoa beans comes from demand for chocolate).

Step 3: Apply to the question A torch and batteries are used together to provide light. Neither works without the other, and they are not substitutes. A torch is not a raw material used to make batteries, or the other way round. So this is a case of complementary (joint) demand.

Step 4: Answer The correct option is C. complementary demand.

Tip: Think "go together" for complementary goods. Pairs like pen and ink, shoes and socks, and torch and batteries are classic examples. If goods "replace" each other, it is competitive demand. If one is an input for making another, it is derived demand. If one good has many uses, it is composite demand.