GATE | GATE-CS-2009 | Question 55

Consider the following relational schema: 
 

Suppliers(sid:integer, sname:string, city:string, street:string)
Parts(pid:integer, pname:string, color:string)
Catalog(sid:integer, pid:integer, cost:real)

Consider the following relational query on the above database: 
 

SELECT S.sname
    FROM Suppliers S
        WHERE S.sid NOT IN (SELECT C.sid
                            FROM Catalog C
                            WHERE C.pid NOT IN (SELECT P.pid  
                                                FROM Parts P
                                                WHERE P.color<> \'blue\'))

Assume that relations corresponding to the above schema are not empty. Which one of the following is the correct interpretation of the above query?
 

(A)

(B)

(C)

(D)

(E)