Ethers are prepared from alcohols by Williamson synthesis. Heating ethanol with sulfuric acid at $413 \ K$ gives ethoxyethane. Match the ether compounds in Column-$I$ with the products formed upon heating with $HI$ in Column-$II$.

Column-$I$ (Ether)	Column-$II$ (Product)
$(A)$ $CH_3CH_2-CH(CH_3)-CH_2-OCH_2CH_3$	$(i)$ $CH_3OH + CH_3-C(CH_3)_2-I$
$(B)$ $CH_3CH_2CH_2-O-C(CH_3)_2CH_2CH_3$	(ii) $C_6H_5OH + C_6H_5CH_2I$
$(C)$ $C_6H_5CH_2-O-C_6H_5$	(iii) $CH_3CH_2CH_2OH + CH_3CH_2-C(CH_3)_2-I$
$(D)$ $CH_3-C(CH_3)_2-O-CH_3$	(iv) $CH_3CH_2-CH(CH_3)-CH_2OH + CH_3CH_2I$

(A-IV, B-III, C-II, D-I) The reaction of ethers with $HI$ follows $S_N1$ or $S_N2$ mechanisms depending on the nature of the alkyl groups.
$(A)$ $CH_3CH_2-CH(CH_3)-CH_2-OCH_2CH_3$ is a primary ether. Cleavage occurs at the less hindered side,giving $CH_3CH_2-CH(CH_3)-CH_2OH$ and $CH_3CH_2I$ $(A \rightarrow iv)$.
$(B)$ $CH_3CH_2CH_2-O-C(CH_3)_2CH_2CH_3$ contains a tertiary alkyl group. Cleavage occurs via $S_N1$ to form the stable tertiary carbocation,giving $CH_3CH_2CH_2OH$ and $CH_3CH_2-C(CH_3)_2I$ $(B \rightarrow iii)$.
$(C)$ $C_6H_5CH_2-O-C_6H_5$ has a benzyl group and a phenyl group. The $C-O$ bond between the benzyl carbon and oxygen breaks,giving $C_6H_5CH_2I$ and $C_6H_5OH$ $(C \rightarrow ii)$.
$(D)$ $CH_3-C(CH_3)_2-O-CH_3$ contains a tertiary alkyl group. Cleavage occurs via $S_N1$ to form the stable tertiary carbocation,giving $CH_3OH$ and $CH_3-C(CH_3)_2I$ $(D \rightarrow i)$.