Bipartite Graphs and Matchings · Challenge problem

Applicants $A,B$ are each qualified only for job $1$; applicant $C$ is qualified for jobs $1$ or $2$; applicant $D$ is qualified for jobs $3$ or $4$. Out of all $15$ nonempty subsets of $\{A,B,C,D\}$, how many violate Hall's condition (have $|N(S)| < |S|$)?