Which of the following is known as liquid gold?

Petroleum, usually referred to as crude oil or liquid gold, is a naturally occurring liquid mixture made up primarily of hydrocarbons that is yellowish-black in color and is found in geological formations. Both naturally occurring unprocessed crude oil and petroleum-based products made of refined crude oil are referred to as petroleum. Petroleum is a fossil fuel that is created when massive amounts of extinct creatures, primarily zooplankton and algae, are buried beneath sedimentary rock and exposed to intense heat and pressure over an extended period of time. Oil drilling has largely been used to recover petroleum. After studying structural geology, analysing sedimentary basins, and characterising reservoirs, drilling is done. Other unconventional assets, such oil sands and oil shale, have also been exploited as a result of recent technological advancements.