C-10-Q118mediumsingle_mcqFinal hydrated oxide formed in rust is written as—aFe2O3⋅3H2O\mathrm{Fe_2O_3 \cdot 3H_2O}Fe2O3⋅3H2ObFe2O3\mathrm{Fe_2O_3}Fe2O3cFeOOH\mathrm{FeOOH}FeOOHdFe(OH)2\mathrm{Fe(OH)_2}Fe(OH)2