C6H6 is a diamagnetic substance, as it is weakly repelled by a magnetic field. CrO2 is a ferromagnetic substance, which is attracted very strongly by a magnetic field. MnO is an antiferromagnetic substance as its domains cancel out each other's magnetic moment. Fe3O4 (magnetite) is a ferrimagnetic substance because in it the magnetic moments of the domains are aligned in parallel and anti-parallel direction in unequal number. Fe3+(3d5) is paramagnetic because of the presence of unpaired electrons. Thus, the correct match is i−5,ii−3,iii−1,iv−2,v−4