Which one of the following reactions will not lead to the desired ether formation in major proportion? (iso- Bu ⇒ isobutyl, sec- Bu ⇒ sec-butyl, nPr…

Which one of the following reactions will not lead to the desired ether formation in major proportion? (iso- $\displaystyle \mathrm{Bu} \Rightarrow$ isobutyl, sec- $\displaystyle \mathrm{Bu} \Rightarrow$ sec-butyl, $\displaystyle \mathrm{nPr} \Rightarrow \mathrm{n}$-propyl, $\displaystyle { }^{\mathrm{t}} \mathrm{Bu} \Rightarrow$ tert-butyl, $\displaystyle \mathrm{Et} \Rightarrow$ ethyl)