Fe+concentrated sulpuric acid

Fe is oxidized to Fe2+ by conc. H2SO4 since conc. H2SO4 still is not strong enough.
Acidified MnO4- and Cr2O7 are very strong oxidizing agents(stronger than conc. H2SO4). They can oxidize Fe immediately to Fe3+.

Fe is oxidized to +3 as conc H2SO4 is a very strong OA.

If Fe is oxidized to Fe2+, as you know, Fe2+ is a strong RA, it will reduce H2SO4 and is self-oxidized to Fe3+.

Therefore the answer is +3

fe will go to fe3+, as conc. sulphuric acid is a strong oxidizing agent.
ADDItion:chlorine is a also strong oxidizing agent,when fe reacts with Cl2,the compound is fecl3