Answer:
The answer to your question is: the third option
Step-by-step explanation:
SO₄ ⁻²
Polyatomic ion is a molecule composed by 2 or more atoms, so SO₄⁻² is a polyatomic ion.
Cation: is an ion that has a positive charge.
Anion: is an ion that has a negative charge.
so SO₄ ⁻² is a polyatomic anion because it is composed by two elements and has a negative charge.
It is a polyatomic anion because it has more than one atom and a negative charge.