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

1. A. B, A, D, C
2. B. B, A, C, D
3. C. A, A, C, D
4. D. A, A, D, C

Answer: C

Explanation

Let’s analyze the given sequence: A_BCD_BBCDABC_DABC_D. The pattern appears to be a repeating block where one letter is duplicated in each subsequent block. Let’s assume the base block is ABCD. The pattern seems to be:
1. A A BCD (A is duplicated)
2. A B BCD (B is duplicated)
3. A B C C D (C is duplicated)
4. A B C D D (D is duplicated)
Applying this pattern to the given sequence:
– For A_BCD, the first block should be A A BCD. So, the first blank is A.
– For _BBCD, the second block should be A B BCD. So, the second blank is A.
– For ABC_D, the third block should be A B C C D. So, the third blank is C.
– For ABC_D, the fourth block should be A B C D D. So, the fourth blank is D.
Therefore, the missing letters are A, A, C, D. This is a complex series completion problem requiring careful pattern recognition.