An industry is best described as

Step 1: Analyze the question The question asks for the best definition of an industry in Economics.

Step 2: Explain the concept In Economics, an industry is not a single firm. It is a group of firms that produce the same or closely related goods or services. Examples are the Nigerian cement industry (Dangote, BUA, Lafarge), the banking industry, and the telecommunications industry (MTN, Airtel, Glo).

A firm is a single business organization. A factory or plant is a physical place where production takes place.

Step 3: Evaluate the options

• A. Firm that sells a set of closely related commodities. This describes a single firm, not an industry. ✗
• B. A factory that produces different lines of product. This describes a factory or plant, and a single one at that. ✗
• C. A group of firms that sells a closely related set of products. This is the correct definition: many firms, with similar products. ✓
• D. Industrial concern that is into production and selling of goods. This is vague and describes one business, not a collection of firms. ✗

Step 4: Answer The correct option is C.

Tip: Remember "Industry = Intersection of many firms." If an option says "a group of firms," it is usually describing an industry. If it names a single firm or factory, it is not.