In the chemical reactions,



the compounds $$'A'$$ and $$'B'$$ respectively are

Consider the following bromides :



The correct order of $${S_N}1$$ reactive is

The main product of the following reaction is

$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,$$ $${C_6}{H_5}C{H_2}CH\left( {OH} \right)CH{\left( {C{H_3}} \right)_2}\buildrel {conc.{H_2}S{O_4}} \over \longrightarrow \,?$$

Which one of the following has an optical isomer ?
(en = ethylenediamine)