Question $5.$ Given a schema consisting of a relation $R$ over attributes $A,B,C$

$($in this order$)$ and a relation $S$ over attribute $C,$ translate the following relational

algebra expressions $($on sets$)$ into equivalent relational calculus queries:

$($a$){}_{AC}({}_A(R))-S$

$($b

Only the RA to RC rules presented in class are allowed. Where needed, transform

the given query using relational algebra equivalences. Please detail all the steps

of the translation.