Answer
a) Manganese (II) Carbonate
b) Gold (I) Sulfate
c) Magnesium Phosphate
d) Iron (III) Bicarbonate or Iron (III) Hydrogen Carbonate
Work Step by Step
$a) MnCO_{3}$ = Manganese (II) Carbonate
$b) Au_{2}SO_{4}$= Gold (I) Sulfate
$c) Mg_{3}(PO_{4})_{2}$= Magnesium Phosphate
$d) Fe(HCO_{3})_{3}$= Iron (III) Bicarbonate or Iron (III) Hydrogen Carbonate