Describe the relations that would be produced by the following tuple relational calculus expressions:

(a) {H.hotelName | Hotel(H) H.city = ‘London’}

(b) {H.hotelName | Hotel(H) ($R) (Room(R)  H.hotelNo = R.hotel No R.price >50)} 

(c) {H.hotelName | Hotel (H)  ($B) ($G) (Booking(B) Guest(G) H.hotelNo = B.hotelNo B.guest No = G.guestNo G.guestName = ‘John Smith’)}

(d) {H.hotelName, G.guestName, B₁.dateFrom, B₂.dateFrom | Hotel (H) Guest(G) Booking (B1) Booking(B₂)  H.hotelNo = B1.hotelNo G.guestNo = B1.guestNo B₂.hotelNo = B1.hotelNo B2.guestNo = B1.guestNo  B2.dateFrom ≠ B1.dateFrom}