Among the following structures, the one which is not a resonating structure of others is:

In which of the following is the first resonating structure less stable compared to the second one?

Compare the ease of carbon-carbon bond rotation across $A, B,$ and $C$.

Which of the following species has a positive charge that is not involved in resonance?

Given below are two statements.
Statement $I :$ The dipole moment of $CH_3-CH=C(CH_3)-CH=O$ is greater than $CH_3-CH_2-CH_2-CH=O$.
Statement $II :$ $C_1-C_2$ bond length of $CH_3-CH=CH-CH=O$ is greater than $C_1-C_2$ bond length of $CH_3-CH_2-CH_2-CH=O$.
In the light of the above statements,choose the correct answer from the options given below $:$

Compare the carbon-carbon double bond rotation energy for the following compounds $A$,$B$,and $C$: