Which of the following statements about a relation R in first normal form (1…

Answer: The true statements are "R can have a multi-attribute key" and "R cannot have a composite attribute."

Explanation:

• R can have a multi-attribute key — True. A multi-attribute (composite) key is simply several attributes combined to uniquely identify tuples. 1NF places no restriction on keys being single-attribute.

• R cannot have a foreign key — False. Foreign keys are allowed in relations; they express relationships between tables. 1NF concerns atomicity of attribute values and absence of repeating groups, not relationships between relations.

• R cannot have a composite attribute — True. 1NF requires that each attribute value be atomic (indivisible). Composite attributes are attributes that can be decomposed into subparts and therefore violate 1NF; they should be broken into separate attributes or related relations.

• R cannot have more than one candidate key — False. A relation can have multiple candidate keys. The number of candidate keys is not restricted by 1NF.

Key point: 1NF is about atomic attribute values and no repeating groups; it does not prohibit composite keys, foreign keys, or multiple candidate keys.