Which of the following pairs are not resonating structures?

$(i)$ Identify the less stable resonance structure and $(ii)$ give its reason for the following pairs.

Which of the following compounds will not exist as a resonance hybrid? Give a reason for your answer.
$(a)$ $CH_3OH$
$(b)$ $RCONH_2$
$(c)$ $CH_3CH=CHCH_2NH_2$

$CH_3-C(=O)-OCH_3$. In the given structure,the bond between carbonyl carbon and oxygen is $a$ and the bond between oxygen and methyl group is $b$. The correct relation between the bond lengths $a$ and $b$ is:

Draw the resonance structures of $NO_2$, state its shape, and indicate the bond angle and bond length.

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: