b. Consider a relation R = {A, B, C, D, E} with the following dependencies. {A, B} ⇒ {C} {C, D} ➜ {E} {D, E} → {B} Is AB a candidate key of R? What about ABD? Explain your answer.

There have been several actors who have played the titular character in the British sci-fi series Doctor Who since the show began in the early 1960s. In 2005 the series was rebooted and Christopher Eccleston, David Tennant, Matt Smith, Peter Capaldi, and Jodie Whittaker have all played the Doctor since. Several Whovians (fans of the show) were asked to rank the actors of the Doctor from their favorite to their least favorite. The results are in the preference schedule below using the initials of each actor (so CE = Christopher Eccleston; DT = David Tennant; etc.).   6 8 12 16 17 18 23 20 1st Choice CE DT DT DT MS MS PC JW 2nd Choice MS CE PC PC JW CE JW CE 3rd Choice DT JW CE JW CE DT DT PC 4th Choice PC MS JW MS PC PC CE DT 5th Choice JW PC MS CE DT JW MS MS Is there a Condorcet winner?Answer:  Explain:   Do any of the voting methodsPlurality Method, Instant…

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