How many moles of sulfate ions are in 100 ml of a solution of 0.0020 m fe2(so4)3?

The  number  of  sulfate ions that are in 100 ml  of a solution of 0.0020 M  Fe2(SO4)3   is    6 x10  ^-4  moles

    calculation
 find the  moles  of   Fe2(SO4)3   that dissociated
  moles =  molarity  x volume  in liters
volume  in liters = 100/1000 = 0.1  liters
molarity =0.002 M
moles  =  0.002  x0.1  =2 x10 ^-4  moles

write  the  equation for dissociation
Fe2(SO4)3 =  2fe^3+  +  3 SO4^2-

by use of mole ratio  between  Fe2(SO4)3  to   SO4^2-  which is  1:3  therefore  the moles of SO4^2- is

=  0.0002  x3 = 6   x10  ^-4 moles

Ibelieve the answer is d