Q. Identify the pair which does not represent substitute goods from the following options:
Answer: Pen and Ink
Notes: Substitute goods are items that can be used in place of another, such as tea and coffee or jaggery and sugar. On the contrary, complementary goods are objects that must be used together, for instance, a pen (option 2) needs ink to function, making them complementary rather than substitutes. Understanding the nature of goods and their interrelationship is important in the field of economics.