Concept:Crude oil is a liquid mineral found deep beneath the earth's surface, so it is extracted by boring holes rather than by digging solid rock.
Explanation:Crude oil is trapped inside porous underground rock formations.
Geologists first sample and test the rocks to locate traces of oil.
When oil is discovered, a well is sunk to reach the deposit.
A drilling rig is then used to penetrate the rock layers and bring the oil to the surface.
This process is called the drilling method.
Open-cast, underground, and shaft methods are meant for solid minerals such as coal or gold, not for liquid crude oil.
Drilling is therefore the correct mining method for crude oil.
Answer:D. drilling method