Directed Graphs and Network Flows · Medium problem

In the network with capacities $c(s,a)=7$, $c(s,b)=5$, $c(a,b)=3$, $c(a,c)=5$, $c(b,c)=2$, $c(b,t)=4$, $c(c,t)=7$, compare the four cuts $S=\{s,a\}$, $S=\{s,b\}$, $S=\{s,a,b\}$, and $S=\{s,a,c\}$ (each with $T=V\setminus S$). What is the smallest of their four capacities?