paramagnetism vs. dimagnetism
Para-magnetism: Para-magnetism refers to the electronic configuration of an atom having one or more unpaired electron. That means an atom can be called para-magnetic if it has one or more unpaired electron. Now if atom A and B has no unpaired electron they have same para-magnetism (in this case zero). If they both have one unpaired electron still they have same para-magnetism (Here it's one).
Now look at the electronic configuration of the above sated options::
$Mn :: [Ar]3d^54s^2$
$Mn^{2+} :: [Ar] 3d^5$
$Fe :: [Ar]3d^64s^2$
$Fe^{3+} :: [Ar] 3d^5$
So they all have five unpaired electron. That's why they have same paramagnetism.