निम्नलिखित में से ऊर्जा के पारंपरिक स्रोतों के सही समूह का चयन कीजिए:

Which country is the leading producer of coal in the world?

Minerals that lie near the earth's surface and are simply dug out without deep drilling are extracted by the process known as:

Which of the following mining methods is specifically used to extract minerals lying near the surface of the Earth by simply digging them out?