Which of these statements are correct about ${\mathrm{NO}}_3^{-}$?

Salt of $N{O}_3^{-}$ gives brown pungent fumes with concentrated $H_{2}S{O}_4$ and copper turnings.

Brown fumes (obtained in option A) gives blue colour when a paper dipped in  $\mathrm{KI}-$ starch solution come in contact with these fumes.

Water soluble salt of $N{O}_3^{-}$ gives brown ring at the junction of two liquids of   $conc.H_{2}S{O}_4$and a solution of nitrate and ferrous sulphate solution.

On reaction with $dil.H_{2}S{O}_4$ nitrate salt decomposes to give NO.