The compound with molecular formula C₈H₁₀ which will give two isomers on electrophilic substitution with ${\mathrm{Cl}}_2/{\mathrm{FeCl}}_3$ is

• A

  Ethyl benzene

• B

  m-dimethyl benzene

• C

  O-dimethyl benzene

• D

  p-dimethyl benzene