Which of the following statements is correct ?

Answer: The correct statement is "Aggregation is a weak type of association between two classes with partial ownership."

Explanation:

• Aggregation is a weak association where the whole and its parts have independent lifecycles; parts can exist independently of the whole and ownership is partial or shared.

• Composition is a strong association that implies full ownership and coincident lifetimes: when the whole is destroyed, the parts are usually destroyed as well.

• UML notation: aggregation is represented by a hollow diamond at the whole end; composition is represented by a filled (black) diamond.

• How to decide: if the part can exist on its own outside the relationship, it is aggregation; if the part cannot reasonably exist without the whole, it is composition.

• Examples: aggregation — a department and its professors (professors can exist independently); composition — a house and its rooms (rooms are integral to the house in the modeled context).

• Therefore, statements that call aggregation "strong" or assert "full ownership" are incorrect because those terms describe composition, not aggregation.