When HCl is added to cobalt nitrate solution at room temp, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. On the basis of this information mark the correct answer

$\begin{array}{l}{\left[Co{\left(H_{2}O\right)}_6\right]}_{\left(aq\right)}^{3+}+4C{l}^{-}\left(aq\right)\rightleftharpoons {\left[CoC{l}_4\right]}_{\left(aq\right)}^{2-}+6H_2{O}_{\left(aq\right)}\\ Pink Blue\end{array}$