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

(A AND C) $CH_3OH$ does not contain $\pi$-electrons and hence it cannot be regarded as a resonance hybrid.
$(b)$ The structure of $RCONH_2$ contains a conjugated system involving the lone pair on $N$ and the $C=O$ $\pi$-bond,allowing for resonance.
$(c)$ $CH_3CH=CHCH_2NH_2$ contains a $\pi$-bond,but it is not in conjugation with the lone pair on $N$ due to the presence of the $sp^3$ hybridized $CH_2$ group,which acts as an insulator. Thus,it does not exhibit resonance.
Therefore,both $(a)$ and $(c)$ do not exist as resonance hybrids.