Chapter 8.7, Problem 2CP

How many resonance structures can be drawn for the nitrite ion $\left({\text{NO}}_{\text{2}}^{\text{-}}\right)$ ? (N and O must obey the octet rule.)

$\begin{array}{l}\text{a)}\hfill \\ \text{1}\hfill \\ \text{b)}\hfill \\ \text{2}\hfill \\ \text{C)}\hfill \\ \text{3}\hfill \\ \text{d)}\hfill \\ \text{4}\hfill \\ \text{e)}\hfill \\ \text{5}\hfill \end{array}$