Which of the following statements is correct?
- AAn unsaturated hydrocarbon is one in which more solute can dissolve.
- BMembers of a homologous series each differ from the next by a $-\text{CH}_2-$ unit.
- CStructural isomers have the same displayed formula but different structural formulae.
- DThe general formula of the carboxylic acid homologous series is $\text{C}_n\text{H}_{2n}\text{COOH}$.