1. **Stating the problem:** We are given a sequence pattern: A-BBC-AAB-CCA-BBCC and asked to find which of the options 1. ACBA 2. BACB 3. ABBA 4. CABA fits as the right answer. 2. **Analyzing the pattern:** The sequence is divided into groups separated by dashes: A, BBC, AAB, CCA, BBCC. 3. **Looking for repetition or rules:** - The first group is A. - The second group is BBC (two Bs and one C). - The third group is AAB (two As and one B). - The fourth group is CCA (two Cs and one A). - The fifth group is BBCC (two Bs and two Cs). 4. **Observing the pattern:** Each group seems to have letters repeated twice and one letter once, except the last group which has two Bs and two Cs. 5. **Checking the options:** - Option 1: ACBA - Option 2: BACB - Option 3: ABBA - Option 4: CABA 6. **Matching the pattern:** The pattern seems to cycle through letters A, B, C with repetitions. 7. **Testing each option against the pattern:** - ACBA: A, C, B, A - fits the pattern of letters used. - BACB: B, A, C, B - also fits. - ABBA: A, B, B, A - fits the repetition pattern. - CABA: C, A, B, A - fits as well. 8. **Conclusion:** Since the original sequence ends with BBCC (two Bs and two Cs), the option that best continues the pattern of letter repetition and order is **ABBA** (option 3), which has two Bs in the middle and A at the ends, matching the repetition style. **Final answer:** 3. ABBA