Which of the following set of letters complete the letter series, when sequentially placed at the gaps?_ ab _ b _ aba _ _ abab*abbaaabbabaaabaabaab

To determine which set of letters completes the sequence "ab _ b _ aba _ _ abab*abbaaabbabaaabaabaab", let's analyze the pattern and complete the missing letters.

Step 1: Break Down the Problem

We will denote the given series and try to find the missing letters.

The series starts with:

• ab _ b _ aba _ _ abab

Step 2: Identify the Patterns

By examining the series, it appears that the sequence involves a combination of "ab" and "ba".

1. The first gap (after "ab") could likely be "a" to maintain the alternating pattern. So it becomes "aba".
2. The second gap (after "b") should continue with "a": "bab".
3. The third gap (after "aba") could again be "b", forming "abab".
4. The last gap (just before the asterisk) might similarly be expected to be "a": "ababa".

If we substitute these letters into the blanks:

• ababaabababab

Step 3: Verify the Continuity

We then need to verify if this substitution maintains consistency in the letter sequence:

• Original: ab _ b _ aba _ _ abab
• Substituted: aba b aba b abab

This follows the pattern of alternating "a" and "b".

Final Answer

Thus, the letters that complete the series are:

• 1. a
• 2. a
• 3. b
• 4. a

So the complete sequence is ababababaab.