a - bbc - aab - c ca - bbc c

Options

A. bacb
B. acba
C. abba
D. caba

Explanation

To solve the series: A - BBC - AAB - CCA - BBC C, we need to identify the pattern and complete the missing part of the series.

### Step-by-Step Solution:

1. **Identify the Pattern**:
The series consists of groups of letters. Let's break down the existing groups:
- 1st group: A
- 2nd group: BBC
- 3rd group: AAB
- 4th group: CCA
- 5th group: BBC C

2. **Look for Repetitions**:
Notice that the letters are repeating in pairs:
- The first letter is A.
- The second group has two B's and one C.
- The third group has two A's and one B.
- The fourth group has two C's and one A.
- The fifth group has two B's and one C.

3. **Determine the Missing Group**:
The missing group appears to follow a pattern where each group has a combination of letters that increase in pairs. The sequence seems to be alternating between A's, B's, and C's.

4. **Fill in the Missing Group**:
- Before the double C (in CCA), we should have double B (BBC).
- Before the double A (in AAB), we should have A.
- Therefore, the missing part should be A.

5. **Final Sequence**:
After filling in the missing part, the complete sequence is:
- A - BBC - AAB - CCA - BBC C

### Conclusion:
The missing part in the series is **A**.