The correct answer is: B. Carbon
Diamond is an allotrope of carbon, a chemical element with the symbol C and atomic number 6. It is a member of the group 14 elements in the periodic table: carbon is the second-lightest element in the group and is a solid at standard temperature and pressure.
Diamond is one of the hardest materials known and is the most widely used gemstone. It is also used in industrial applications, such as cutting tools and abrasives.
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a metalloid in the carbon group in the periodic table. It is a silvery-white metalloid that is chemically similar to silicon and tin.
Silicon is a chemical element with the symbol Si and atomic number 14. It is a tetravalent metalloid and semiconductor in the group 14 of the periodic table. It is a member of the carbon group and is a major component of the Earth’s crust.
Sulphur is a chemical element with the symbol S and atomic number 16. It is a non-metallic, multivalent pale yellow solid that is widely distributed in nature. It is a member of the chalcogen group in the periodic table and is chemically similar to oxygen and selenium.
In conclusion, diamond is an allotrope of carbon, not germanium, silicon, or sulphur.