Consider the E$/$R diagram above, and suppose that a$1$ and a$2$ are entities of entity set A$,$ b$1$

and $b2$ are entities of set $B,$ and $c1$ and $c2$ are entities of set $C.$ The arrows limit the possible

relationship sets for $R$ and $S.$ Describe the limitations on these relationship sets. Then, confirm

your understanding by identifying which of the following relationships sets for $R$ and $S$ are

possible according to the diagram.

$R=\{(a1,b1),(a2,b2)\}$;$S=\{(b1,c1)\}$

$R=\{(a1,b1)\}$;$S=\{(b1,c1),(b2,c2)\}$

$R=\{(a1,b1),(a2,b2)\}$;$S=\{\}$

$R=\{(a1,b1),(a2,b1)\}$;$S=\{(b1,c2)\}$