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Consider the following schema :
Sailors (sid, sname, rating, age)Boats (bid, bname, colour)Reserves (sid, bid, day)
Two boats can have the same name but the colour differentiates them. The two relations
ρ (Tempsids, (Ⲡ sid, bid Reserves)/(Ⲡ bid ( σ bname ='Ganga' Boats))),Ⲡ sname (Tempsids ⋈ Sailors)
If / is division operation, the above set of relations represents the query
(A) Names of sailors who have reserved all boats called Ganga
(B) Names of sailors who have not reserved any Gangaboat
(C) Names of sailors who have reserved at least one Gangaboat
(D) Names of sailors who have reserved at most one Ganga boat
nan