Given the table below, what is the chemical formula for a compound between Na and the sulfate ion SO4 -2?
nitrate ion NO3 -1
phosphate PO4 -3
sulfate SO4 -2
acetate C2H3O2 -1
ammonium NH4 +1
chromate CrO4 -2
carbonate CO3 -2
dichromate Cr2O7 -2
permanganate MnO4 -1
sulfite SO3 -2
a)NaSO4

b)Na2SO4

c)Na(SO4)2

d) Na2(SO4)2