Before defining the logical schema of the database, answer the following questions: a. Can you use the name of the hotel as a primary key? Justify your answer. b. Can you use the flight number as a primary key to identify a flight? Justify your answer and, in case of a negative answer, propose a solution. c. Knowing that it is unlikely that two reviews have the same textual content, would you use it as a primary key? Justify your answer. d. Knowing that the IATA code uniquely identifies an airport, would you choose it as a primary key for the entity Airport? Justify your answer.