Correct Option (c)
All three activities listed are recognized and actively discussed strategies for carbon capture and sequestration (CCS), often categorized under geoengineering or negative emission technologies.
1. Spreading finely ground basalt rock on farmlands extensively: This method, known as enhanced rock weathering, involves accelerating natural geological processes. Finely ground silicate-rich rocks like basalt react with atmospheric CO₂ and water to form stable carbonate minerals, thereby removing CO₂ from the atmosphere and sequestering it in soils. This process can also improve soil health and fertility.
2. Increasing the alkalinity of oceans by adding lime: Ocean alkalinity enhancement is a proposed technique to increase the ocean's capacity to absorb atmospheric CO₂. Adding alkaline substances, such as lime (calcium hydroxide or carbonate), to seawater promotes the conversion of dissolved CO₂ into stable bicarbonate and carbonate ions, effectively sequestering carbon and potentially mitigating ocean acidification.
3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters: This is a form of geological carbon sequestration. Captured CO₂ is injected into suitable underground geological formations, such as depleted oil and gas reservoirs, deep saline aquifers, or abandoned mines. When injected as carbonated water, CO₂ dissolves and can react with surrounding minerals to form stable carbonate compounds, ensuring long-term storage.
Incorrect Options
Options (a), (b), and (d) are incorrect because all three activities described are valid and extensively researched methods within the broader framework of carbon capture, utilization, and sequestration (CCUS) and climate change mitigation strategies.