aab - aa - bbb - aaa - bbb

Options

A. abba
B. baab
C. aaab
D. abab

Explanation

To solve the series completion problem given as: aab - aa - bbb - aaa - bbb, we need to identify the pattern in the series and determine the missing elements.

### Step-by-Step Solution:

1. **Identify the Pattern**:
- The series consists of letters 'a' and 'b'.
- We can observe the frequency of each letter in the sequence:
- The first term is "aab" (2 'a's and 1 'b').
- The second term is "aa" (2 'a's).
- The third term is "bbb" (3 'b's).
- The fourth term is "aaa" (3 'a's).
- The fifth term is "bbb" (3 'b's).

2. **Analyze the Frequency**:
- The sequence alternates between 'a's and 'b's.
- The number of 'a's and 'b's seems to be increasing:
- First term: 2 'a's and 1 'b'
- Second term: 2 'a's
- Third term: 3 'b's
- Fourth term: 3 'a's
- Fifth term: 3 'b's

3. **Determine the Missing Terms**:
- The missing terms are represented by the dashes in the series.
- Following the pattern:
- After "aab", we have "aa" (2 'a's).
- The next term should logically be "bbb" (3 'b's) which we already have.
- After "bbb", we should have "aaa" (3 'a's) which we already have.
- The next term after "aaa" should be "bbb" (3 'b's) which we already have.
- Therefore, the missing term after "aab" should be "bbb".

4. **Final Series**:
- The completed series should be: aab - bbb - aa - bbb - aaa - bbb.

### Conclusion:
The missing term in the series is "bbb".