Explain the below diagram

 

Game GameLoan Game_ID [PK] 1...1 0... Game ID[PK][FK] 0...* 1...1 Gamer_ID Game_Name Game_Author Gamer_ID[PK][FK] Loan_Star [PK] Loan_Duration Gamer Gamer_ID [PK] Gamer_FirstName Gamer_LastName Gamer_Phone Gamer_Email We are still debating what would be the best design to accommodate loan renewals (extensions). We have received new information to the effect that we have to ensure the extensions can be traced to the original loan, because the store wants to enforce a limit on the number of extensions. Which of the following is the best design for such a requirement? (The strong entities Game and Gamer have been omitted in the answers.) A) GameLoan Game_ID[PK][FK] Gamer_ID[PK][FK] Loan_StartDate [PK] Loan_EndDate 1...1 0... Loan Extension Gamer_ID [PK][FK] Game_ID[PK][FK] Extended_On [PK] Extension_No [PK] Extended_Date B) GameLoan Game_ID[PK][FK] Gamer_ID[PK][FK] Loan_StartDate [PK] Loan_EndDate C) GameLoan Game_ID[PK][FK] Gamer_ID[PK][FK] Loan_StartDate [PK] Loan_EndDate D) GameLoan Game_ID[PK][FK] Gamer_ID[PK][FK] Loan_StartDate [PK][FK] Extension_No [FK] Loan_EndDate 1...1 0...* 1...1 0...1 1...1 Loan Extension Gamer_ID [PK][FK] Game_ID[PK][FK] Loan_StartDate [PK][FK] Extension No [PK] Extended_Date Loan Extension Gamer_ID [PK][FK] Game_ID[PK][FK] Loan_StartDate [PK][FK] Extended_Date Loan Extension 0... Gamer_ID [PK] Game_ID[PK] Loan_StartDate [PK] Extension No [PK] Extended Date