The correct order of C-H bond length in ${\mathrm{CH}}_3-{\mathrm{CH}}_3,{\mathrm{CH}}_2={\mathrm{CH}}_2\text{ and }\mathrm{CH}\equiv \mathrm{CH}\text{ is: }$

• A

  $\mathrm{CH}\equiv \mathrm{CH}<{\mathrm{CH}}_2={\mathrm{CH}}_2<{\mathrm{CH}}_3-{\mathrm{CH}}_3$

• B

  ${\mathrm{CH}}_2={\mathrm{CH}}_2<{\mathrm{CH}}_3-{\mathrm{CH}}_3<\mathrm{CH}\equiv \mathrm{CH}$

• C

  ${\text{CH}}_3-{\mathrm{CH}}_3<{\mathrm{CH}}_2={\mathrm{CH}}_2<\mathrm{CH}\equiv \mathrm{CH}$

• D

  All are equal