What is the bond order of the carbon-carbon bond in benzene?

Given below are two statements :
Statement $I$ : Experimentally determined oxygen-oxygen bond lengths in the $O_3$ are found to be same and the bond length is greater than that of a $O=O$ (double bond) but less than that of a single $(O-O)$ bond.
Statement $II$ : The strong lone pair-lone pair repulsion between oxygen atoms is solely responsible for the fact that the bond length in ozone is smaller than that of a double bond $(O=O)$ but more than that of a single bond $(O-O)$.
In the light of the above statements,choose the correct answer from the options given below:

The correct stability order of the following resonance structures of $CH_3-CH=CH-CHO$ is:

Explain the structure of $CO_{3}^{2-}$ ion in terms of resonance.

What is the difference between the resonance structures of $CH_3CH_2COO^{-}$ and $CH_3COOH$?

Draw the resonance structures of $O_3$ and explain its requirement, limitations, and advantages.