In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration? 1. Abandoned and uneconomic coal seams 2. Depleted oil and gas reservoirs 3. Subterranean deep saline formations Select the correct answer using the code given below:

Carbon sequestration involves the capture and long-term storage of atmospheric carbon dioxide (CO2) to mitigate global warming. Geological sequestration is a prominent method where CO2 is injected into deep underground geological formations.

1. Abandoned and uneconomic coal seams: These can be used for CO2 storage. CO2 can be injected into these seams, where it gets adsorbed by the coal, potentially enhancing coal-bed methane recovery (ECBM) while simultaneously storing CO2. This is a recognized method.

2. Depleted oil and gas reservoirs: These are geological formations that have previously held oil and natural gas for millions of years, indicating their ability to contain fluids and gases over long periods. They often have existing infrastructure (wells), and their geology is well-characterized, making them suitable and cost-effective sites for CO2 storage.

3. Subterranean deep saline formations: These are vast geological formations containing highly saline water (brine) that is unsuitable for human use. They are found across many regions globally and possess immense CO2 storage potential due to their large pore volumes and widespread distribution. This is considered the largest potential storage option.

All three options are indeed potential and recognized sites for geological carbon sequestration.