Which of the following compounds will form the precipitate with $\mathrm{aq}.{\mathrm{AgNO}}_3$ solution most readily ?

$\begin{array}{l}R-Cl+AgN{O}_3\underset{ }{\overset{ }{\to }}AgCl\downarrow +R^{+}+N{O}_3^{-}\\ ppt\end{array}$

So one which will form most stable carbocation will give ppt with ${\mathrm{AgNO}}_3$ most readily,.

is most stable of all the carbocations formed.