The answer is D)
The double replacement reaction that takes place in aqueous solution between lead (II) nitrate,
The other product of this reaction is potassium nitrate,
This means that you can determine which ions will act as spectator ions by looking at what the reaction forms. Right from the start, knowing that lead (II) iodide is an insoluble solid, the ions that come together to form this compound cannot be spectator ions.
So the two candidates that stand out are
To double-check, write the complete ionic equation for this reaction
As you can see, the potassium and nitrate ions are present on both sides of the equation, which means that they are indeed spectator ions.
Therefore, you have
The net ionic equation is
Here's how the precipitate looks like