Consider the following activities:
1. Spreading finely ground basalt rock on farmlands extensively
2. Increasing the alkalinity of oceans by adding lime
3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters

How many of the above activities are often considered and discussed for carbon capture and sequestration?

Correct Option: All three

All three activities are widely researched and discussed for carbon capture and sequestration (CCS) and carbon dioxide removal (CDR). Spreading finely ground silicate rocks like basalt enhances enhanced weathering, a natural CDR process. Adding lime/alkalinity to oceans increases their capacity to absorb and sequester atmospheric CO2. Capturing industrial emissions and pumping them into subterranean geological formations in carbonated form is mineral trapping/geological sequestration. Thus, all three are correct.