Using the following schema: Suppliers(sid, sname, address) Parts(pid, pname, color) Catalog(pid, sid, cost, rating) consider the following query: SELECT s.sname, c.cost FROM suppliers s, parts p, catalog c WHERE p.p.d = c.pid AND c.sid-s.sid AND c.rating 15 AND p.name- 'screw driver a) (10 pts) Draw a query tree using selection, projection and cross product (OTx). b) (10 pts) Draw a query tree that optimizes the SQL query using pushing selections