The correct answer is D. Charcoal and diamond.
Charcoal is a form of carbon that is produced by heating wood or other organic materials in the absence of oxygen. Diamond is a form of carbon that is produced by deep geological processes involving high temperatures and pressures.
Charcoal and diamond are both made of carbon, but they have very different structures. Charcoal is a disordered solid with a lot of empty space. Diamond is a very ordered solid with a very dense crystal structure.
Charcoal is a good conductor of electricity, while diamond is a good insulator. Charcoal is also a good absorber of gases, while diamond is not.
Charcoal is used in a variety of applications, including fuel, water purification, and deodorizing. Diamond is used in jewelry, industrial cutting tools, and other applications where a very hard material is needed.
In conclusion, charcoal and diamond are chemically most dissimilar because they have very different structures, properties, and uses.