The correct answer is option B, that is, carbon.
Carbon refers to a chemical element denoted by C, exhibiting atomic number 6. It is tetravalent and nonmetallic, forming four electrons accessible to produce covalent chemical bonds.
Carbon in the form of coal, which is primarily carbon is used as a fuel. Graphite is used for high-temperature crucibles, pencil tips, electrodes, dry cells, and as a lubricant. Diamonds have an application in jewelry, and as they are hard, in the industry they are utilized for drilling, cutting, polishing, and grinding.