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
$$\rho(Tempsids, (\pi_{sid, bid}Reserves)/(\pi_{bid }(\sigma_{bname = 'Ganga'} Boats)))$$,
$$\pi_{sname}(Tempsids \bowtie Sailors)$$
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 Ganga boat

C

Names of sailors who have reserved at least one Ganga boat

D

Names of sailors who have reserved at most one Ganga boat