The correct answer is: A. Allotrope
Allotropes are different forms of the same element that have different physical properties but the same chemical properties. Carbon has many allotropes, including diamond, graphite, and charcoal.
Diamond is a hard, transparent form of carbon that is used in jewelry and other applications. Graphite is a soft, black form of carbon that is used in pencils and lubricants. Charcoal is a porous form of carbon that is used in filters and as a fuel.
Isomers are molecules that have the same chemical formula but different structural formulas. For example, ethanol and dimethyl ether are both isomers of C2H6O.
Isomorphs are minerals that have the same crystal structure but different chemical compositions. For example, calcite and dolomite are both isomorphs of CaCO3.
Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. For example, carbon-12 and carbon-14 are both isotopes of carbon.
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