The ion which exhibits orange red colour in aqueous solution is

Dichromate ion $\left({\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}\right)$ has orange colour. The colour of chromium ion $\left({\mathrm{Cr}}^{3+}\right)$, permaganate ion $\left(Mn{O}_4^{-}\right)$ and maganate ion $\left({\mathrm{MnO}}_4^{2-}\right)$ are green, violet and green respectively.

Hence ,the correct option is ( A).