choose the correct answer :

1 - The primary aspect of a composite attribute is that it

Select one:

a. None of the above

b. Is an attribute that has a set of values

c. Consists of subparts, which represent more basic attributes

d. Is an attribute that can be determined from other attribute values

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2- Let R and S be two given relations. R contains r tuples and Ar attributes, and S contains s tuples and As attributes. the maximum number of attributes of the R S is:

Select one:

a. Ar-As

b. Ts

c. As-Ar

d. Ar

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3- Let R and S be two given relations. R contains r tuples and Ar attributes, and S contains s tuples and As attributes. The minimum number of attributes of the S R is:

Select one:

a. As

b. Ar

c. Ar-As

d. As-Ar