Which order is correct for the decreasing reactivity to ring monobromination of the following compounds
$\begin{array}{l}{C_6}{H_5}C{H_3},\\\,\,\,\,\,\,\,\,\,\,{\rm{I}}\end{array}$$\begin{array}{l}{C_6}{H_5}COOH,\\\,\,\,\,\,\,\,\,\,\,\,\,\,{\rm{II}}\end{array}$$\begin{array}{l}{C_6}{H_6}\\\,\,\,\,{\rm{III}}\end{array}$$\begin{array}{l}{C_6}{H_5}N{O_2}\\\,\,\,\,\,\,\,\,\,\,{\rm{IV}}\end{array}$
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