Canonical cover of a set

Question

Consider the following set of functional dependency on the scheme (A, B,C) A-->BC, B-->C, A--> B, AB-->C The canonical cover for this set is:

(A) A-->BC and B--> C

B. A-->BC and AB--> C

C. A--> BC and A--> B

D. A--> B and B--> C

Answer 1

A->BC  ==> A->B  A->C

                     B->C

                     A->B

                    AB->C   [Extraneous attrib removed]   ==> A->C  

[A->B A->C B->C    ]  A->C is redundant

A->B

B->C

D is the answer.

https://www.youtube.com/watch?v=Q8j4lYeVIek​

Answer 2

The answer must be D.Here A-B and B->C must be the only the FDs derived after applying the redundant FD rules.

Answer 3

answer should be option D because with the help of only those two FDs we are able to derive everything.

Answer 4

A-->BC and B--> C


A---> C is transitive 
so min cover should b A-->B and B--> C
 

Comments

why not D? All dependencies are covered by D too right?

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even A->BC and B->C here we could derive A->C through(A->B ,B->C ) THEN why to have A->C again its redundent na i think option d is right

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http://www.sztaki.hu/~fodroczi/dbs/canon_cover_gyak.pdf  

here its given optn D.