Using the data given below find out the strongest reducing agent. EoCr2O4/Cr3+=1.33V, EoCl2/Cl-=1.36V, EoMnO4/Mn2+=1.51V, EoCr3+/Cr=-0.74V

The strongest reducing agent is one which is oxidised most easily, i.e., which has the highest oxidation potential. Cr/Cr3+ has the highest oxidation potential, i.e., (+0.74) so, it is oxidised most easily and, therefore, it is the strongest reducing agent. Hence, option C is correct.