The correct answer is: B. graphite
In graphite, each carbon atom is bound to three other carbon atoms in the same plane, providing a hexagonal array. This structure gives graphite its unique properties, such as its ability to conduct electricity and its use as a lubricant.
A. Propane is a hydrocarbon with the chemical formula C3H8. It is a colorless, odorless gas that is used as a fuel. The carbon atoms in propane are not bonded to each other in a hexagonal array.
C. Diamond is a crystalline form of carbon. The carbon atoms in diamond are arranged in a tetrahedral structure, which gives diamond its strength and hardness.
D. Benzene is a hydrocarbon with the chemical formula C6H6. It is a colorless, flammable liquid that is used as a solvent and a fuel. The carbon atoms in benzene are arranged in a hexagonal ring.