Optimize the following two relational algebra queries (Your marks will depend on how well you present the key ideas of query optimization in your answer). In addition to this, draw the query trees that correspond to queries before and after your optimisation.

(a) BOOKING.CustomerID,Origin,P rice(BOOKING.F lightNo=F LIGHT .F lightNo (BOOKING.CustomerID=CUST OMER.CustomerID(BOOKING F LIGHT CUST OMER)))

(b) R1.CustomerID(R1.CustomerID=R2.CustomerID((R1.Date6=R2.Date)(R1.Origin=0Canberra0) (R2.Origin=0Canberra0) (R1(BOOKING ./ F LIGHT ./ CUST OMER) R2(BOOKING ./ F LIGHT ./ CUST OMER))))