Correct Answer: abcc

Solution : Given:
_bcc_aabc_baab_

To fill the series we have to divide the series — _bc / c _a / abc /_ba / ab_
Let's check the option —
First option: acac; a bc / c c a /abc / a ba / ab c (No repeated pattern has been found.)
Second option: abcc; a bc / c b a / abc / c ba / ab c (abc and cba repeated alternatively.)
Third option: acbc; a bb /c c a / abc / b ba / ab c (No repeated pattern has been found.)
Fourth option: abac; a bb/ c b a / abc / a ba / ab c (No repeated pattern has been found.)

So, the series becomes abccbaabccbaabc. Hence, the second option is correct.