Verbal Reasoning — Association (Always found): Which of the following is always found in factories? Context: Consider what every factory must have to operate as a production unit, across scales and technologies. Choose the option that is invariably present.

Concept
Across traditional and modern setups, a factory is an organized place of production staffed by workers (human labor in various roles; even automated plants require human oversight). Chimneys are not universal; electricity is near-universal but not logically necessary in every historical or minimal setup; sellers are not factory-intrinsic.

Option check

• Chimney — Only in certain kinds of plants.
• Workers — Staffing is essential for operations. Correct.
• Electricity — Extremely common, but not a logical absolute in all eras/contexts.
• Sellers — Sales happen in markets, not necessarily inside factories.

Final Answer
Workers.