The $\mathrm{C}–\mathrm{C}$ bond length in benzene is A. less than $\mathrm{C}–\mathrm{C}$ in ethane B. greater than $C=C$ in ethene C. greater than $C\equiv C$ in ethyne

• Carbon-carbon single bonds can be found in ethane. 
• The nature of benzene is aromatic. In benzene, every carbon-carbon bond has the characteristics of a partial double bond. 
• The carbon-carbon double bond is present in ethylene. 
• Acetylene has a triple bond made of carbon and carbon. 
• Single bonds are longer than partial double bonds, double bonds are longer than triple bonds, and so on. 

Hence, the correct option (C) B and C.