The correct option is D P3+>P5+
Larger the positive charge on the ion smaller will be the size of ion for the same element.
For P3+, there are 15 protons for 12 electrons while for P5+ there are 15 protons for 10 electrons. Thus, in P5+ the valence electrons are more strongly attracted by the nucleus than those of P3+. As a result, there is a larger contraction in the size of P5+ than that of P3+ Hence, P3+ is bigger than P5+.