Answer:
C
Explanation:
We can use process of elimination;
Though the last part of A is true (polyatomic ions do have a positive or negative charge), the first statement would make it false, as the prefix poly- means 'many', such as in 'polymer'.
B is also false, as ions by definition have a positive or negative charge.
C is correct, as if an ion is polyatomic, it must be consisting of multiple atoms, and if it's an ion, it must have a positive or negative charge.
D is incorrect, as ions are used in ionic bonding, which by definition is the bonding of ions. Polyatomic ions are no different, as they can create compounds like NaClO (sodium hypochlorite, better known as bleach), KOH (potassium hydroxide), MgSO4 (magnesium sulfate, better known as Epsom salt) , among others.