The correct answer is option D, Silicon
Rocks are basically made up of elements which are abundant in the Earth’s crust. Since Earth’s crust has rich reserves of silicon and oxygen, it is made up of silicate minerals. The silicate minerals are basically of two types – light (70 % Silica content) and dark (50 % silica content) silicates. Light silicates are knows as quartz, muscovite and feldspar and Dark silicates includes ferromagnesian (consisting of iron and magnesium).
