The correct answer is open-cast mining.
Open-cast mining is a surface mining method in which minerals are extracted from the earth by removing overlying soil and rock. It is the most common method of mining for coal, iron ore, and other minerals that are found near the surface.
Underground mining is a method of extracting minerals from the earth by digging tunnels and shafts below the surface. It is used to extract minerals that are found deep underground, such as copper, gold, and silver.
Placer mining is a method of extracting minerals that are found in loose sediments, such as sand and gravel. It is used to extract minerals such as gold, diamonds, and tin.
Borehole mining is a method of extracting minerals that are found deep underground by drilling a hole and then extracting the minerals using a pump or other device. It is used to extract minerals such as oil, natural gas, and geothermal energy.
Open-cast mining is the most common method of mining in Goa because it is the most cost-effective method for extracting minerals that are found near the surface.