Select the best correct statement below that explains why all three bonds in NO31- have the same length, instead of having a different bond length for the double bond than the single bonds between N and the oxygen atoms.

Question

a. bond lengths for double bonds tend to be longer than single bonds

b. bond lengths for single bonds tend to be shorter than single bonds

c. when resonance occurs, the multiple bond is "spread equally" across all locations where we could draw that same multiple bond