Final answer:
The correct answer is d) CO₃²⁻. It is a polyatomic ion known as the carbonate ion.
Step-by-step explanation:
A polyatomic ion is an ion that is composed of two or more atoms. It carries an overall charge and acts as a single unit in ionic compounds. The correct answer to the question is d) CO₃²⁻. This ion is known as the carbonate ion.
a) ClO₃⁻ is the chlorate ion, b) ClO₄⁻ is the perchlorate ion, and c) MnO₄⁻ is the permanganate ion. All of these ions are examples of polyatomic ions.
On the other hand, CO₃²⁻ consists of one carbon atom bonded to three oxygen atoms, and it is a polyatomic ion that carries a 2- charge.