Qu$$stion $8$

Suppose we have a relation with schema:

$R(A,B,C,D,E)$

If we issue a query of the form

SELECT $???$

FROM R

WHERE $..$

GROUP BY C$,$ D;

What terms can appear in the SELECT list $($represented by $???$ in the above query$)?$ Identify, in the list below, the term that CAN NOT appear

a$.C$

b$.$ A

c$.$ SUM$($E$)$

d$.$ COUNT$(E)$