Another classic example of people replying to the queries 
in hurry..the answer #1, #2, #3, #4 & #7 are WRONG ANSWERS. 
Answer #6 is correct. Answer #5 also seems to be correct to 
me (unfortunatley I can't run & verify it at the moment, 
someone please verify it & let everyone know). 

Ram.g, FYI..EXISTS clause just denotes whether query after 
EXISTS clause returned any row or not, it NEVER give a 
count of the number of rows returned. Here need to find if 
there are more than one rows (i.e count is needed) so 
EXISTS can't be used here.