Consider the sequence
ABC__ABC_DABBCD_ABCD
that follows a certain pattern.
Which one of the following completes the sequence?

Correct Option: DDCA

Consider the sequence: ABC__ABC_DABBCD_ABCD. Let us fill in the blanks by analyzing the repeating or progressive pattern of blocks. The sequence has repeating segments involving letters A, B, C, D. Let us look at the length and structure: Total characters including blanks: Let's divide into blocks or look at the progression. Let's test option (d) 'DDCA': Filling the blanks gives ABC D D ABC C D A B B C D A A B C D. Let's check the pattern of blocks: ABC, ABCD, ABBCD, ABCDD... or similar. Let's test option (d) DDCA in the blanks: ABC D D ABC C D A B B C D A A B C D -> wait, let's write out the sequence with option (d) DDCA: ABC D D ABC C D A B B C D A A B C D. Let's check the groups: ABC, DD, ABC, C, DAB, B, CD, A, ABC, D... wait. Let's examine the exact gaps in ABC__ABC_DABBCD_ABCD: Blank 1, Blank 2, Blank 3, Blank 4. The sequence is: A B C [D] [D] A B C [C] D A B B C D [A] A B C D. Let's check option (d): DDCA. Filling in order: 1st blank = D, 2nd blank = D, 3rd blank = C, 4th blank = A. This matches option (d) exactly. Therefore, option (d) is correct.