= Solution
\b[C is <2-Chloroethyl vinyl ether>, $\mathrm{CH_2=CH-O-CH_2-CH_2Cl}$.] There is one <alkene> and no <carbonyl>. Assign the <carbon-13 NMR> resonances as
$$
\begin{array}{c|c}
\text{site}&\delta_C/\mathrm{ppm}\\\hline
\mathrm{CH_2=}&87.4\\
\mathrm{=CH-O}&151.1\\
\mathrm{OCH_2}&67.8\\
\mathrm{CH_2Cl}&41.9
\end{array}
$$
The strongly differentiated pair of <alkene> shifts is characteristic of a <vinyl ether>; interpreting $151.1$ ppm as a <carbonyl> would leave the unusually shielded unsaturated $87.4$ ppm <carbon> and the three distinct vinylic <protons> unexplained.
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