The correct formula for Lead IV Nitrate is Pb(NO3)4. Pb is the chemical symbol for the element Lead and NO3 for Nitrate. If they are to form a compound it will be Pb 4+ and (NO3)-. In-laws of chemistry, the ions in the lead must be put at the end of the compound it is combined to.
That is how the answer Pb(NO3)4 forms into. And base on the given choices, there is no Pb(NO3)4 but only Pb2(NO3)2, Pb(NO3)2, which is Lead II Nitrate, and Pb4(NO3)2. Lead is soft, malleable, and is resistant to corrosion while nitrate is a salt of nitric acid.