Suppose that we pick the following three tuples from a legal instance of a relation S (S has 100 tuples in total). Relation S has the following schema: (A : integer, B : integer, C : integer). The three tuples are: (1,2,3), (4,2,3), and (5,3,3). Which of the following dependencies can you infer does not hold over S? A. A → B,
B. BC → A,
C. C → B

The correct answer is BC → A, A does not hold over S. we noticed the tuples (1 ,2 ,3 ) and (4 ,2 ,3) which can hold over S)

Explanation:

Solution

No, since in this case the instance of S is provided. so such particular dependencies are unable to breach through such instance, but unable to tell which the dependencies hold towards S.

A functional dependency holds towards only when a relation forms a statement regarding the complete allowed instances of relation.

given the options, i would say your best bet is c. the modem supports up to 56 kbps, which is too low for video streaming. dial up modems use actual phone lines, which only can go up to 56 kbps as that's more than sufficient for traditional phone calls. this is also the reason why when a dial-up modem connects, you hear all those sounds. it's literally using the phone line to establish a connection.