2-Methyl propyl bromide reacts with $$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{O}^{-}$$ and gives 'A' whereas on reaction with $$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$$ it gives 'B'. The mechanism followed in these reactions and the products 'A' and 'B' respectively are :

Correct statements for the given reaction are :

A. Compound '$$\mathrm{B}$$' is aromatic

B. The completion of above reaction is very slow

C. 'A' shows tautomerism

D. The bond lengths of C-C in compound $B$ are found to be same

Choose the correct answer from the options given below:

Compound 'B' is

Product [X] formed in the above reaction is :