Composition means a)that data fields should be declared private b)that a class extends another class c)that a variable of supertype refers to a subtype object d)that a class contains a data field e)that references another object

The answer is "Option d".

Explanation:

In programming, Composition is a method, which is used to applying multiplicating and additive probability laws to evaluate the probabilities, It is a unique method, that uses math function, it also use to include data field, and other choices are wrong, that can be described as follows:

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