Which of the following chains of cause and effect is correct?

The correct answer is Option (1) → Thermal power plants → emit large quantities of carbon dioxide → global warming

Carbon dioxide is a greenhouse gas, and more greenhouse gases cause global warming. Thermal power plants emit large quantities of it.

Option (1) Thermal power plants → emit large quantities of carbon dioxide → global warming — Correct. Each link in this chain is right.

Option (2) Thermal power plants → release chlorofluorocarbons → ozone depletion — Incorrect. CFCs come from air-conditioners, refrigerators and aerosol propellants, not from power plants.

Option (3) Hydroelectric projects → produce fly ash → pollution of water bodies — Incorrect. Fly ash comes from thermal power plants, not from hydroelectric projects.

Option (4) Mini-hydel plants → inundate forests → loss of green cover — Incorrect. Large hydroelectric projects inundate forests. Mini-hydel plants do not change the land use pattern.