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

For the given compounds,the correct order of resonance energy is:
$(I)$ $CH_2=CH-CH=CH-OCH_3$
$(II)$ $CH_2=CH-C(OCH_3)=CH_2$
$(III)$ $CH_2=CH-OCH_3$

Resonance effect is not observed in

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 $:$

The order of relative stability of the contributing structures is:
$I: CH_2=CH-CHO$
$II: ^+CH_2-CH=CH-O^-$
$III: ^-CH_2-CH=CH-O^+$
Choose the correct answer from the options given below:

Which of the following is the most unstable resonating structure?