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

Among the following,the least stable resonance structure is

In graphite, the $C-C$ bond length $(141.5 \, pm)$ is found to be shorter than the normal $C-C$ single bond length $(154 \, pm)$. This anomaly occurs due to:

In the anion $HCOO^-$,the two carbon-oxygen bonds are found to be of equal length. What is the reason?

Although $ClO_2$ is an odd-electron molecule,it does not dimerize because...

What is the carbon-carbon bond length in benzene (in $pm$)?