Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species $\;O^{2-} ,S^{2-} ,N^{3-} ,P^{3-}\;$ ?

Question

$(a)\;O^{2-} < N^{3-} < S^{2-} < P^{3-} \qquad(b)\;O^{2-} < P^{3-} < N^{3-} < S^{2-} \qquad(c)\;N^{3-} < O^{2-} < P^{3-} < S^{2-} \qquad(d)\;N^{3-} < S^{2-} < O^{2-} < P^{3-}$