$S$ and $T$ are binary relations on the set $\{a,b,c,d\}$ and are defined as follows:

$S=\{(a,b)(b,b),(d,c),(c,b)\}$

$T=\{(d,a),(b,a),(a,d),(b,c)\}$

a$.$ Draw the arrow diagrams for both $S$ and $T.$

b$.$ What is the binary relation set S o $T?($Give all the ordered pairs$).$

c$.$ Draw the arrow diagram for $S$ o $T$