Answer:
D. Silicon
Step-by-step explanation:
Silicon is very abundant in nature, in the entire universe it is the 7th most abundant, behind the following elements: hydrogen, helium, neon, oxygen, nitrogen and carbon. In the Earth's crust, it is the second largest (27.7%), second only to oxygen.
However, it is never found naturally in isolation, it is always combined with some other element, or chemical compound. For this reason, it was first prepared in the laboratory, in 1824, by the Swedish chemist Jöns Jacob Berzelius, by heating silicon tetrafluoride with potassium.