Arranging the sequence of A, B, C, D on the basis of age in descending order,
A > B, C > A, D ≯ i.e., D < B or D = B
If they are arranged according to the given option, then C>A>B=D
As per the question, 'D' is not older than 'B'. 'D' is either younger to or of the same age as B. Therefore, according to option (3), 'B' and 'D' both are of same age.
Hence, the required answer is (3).