Which of the following reaction(s) can be used for the preparation of alkyl halides? i. $CH_3CH_2OH$ + $HCl^{Anhyd.ZnCl_2}$ $\longrightarrow$ ii. $CH_3CH_2OH$ + HCl $\longrightarrow$ iii. $(CH_3)_3COH$ + HCl $\longrightarrow$ iv. $(CH_3)_2CHOH$ + $HCl^{Anhyd.ZnCl_2}$ $\longrightarrow$