In alphabet series, some alphabets are missing which are given in that order as one of the alternatives below it. Choose the correct alternative.
c _ ac _ aa _ aa _ bc _ bcc
ab _ aa _ bbb _ aaa _ bbba
abca _ bcaab _ aa _ caa _ c
ab _ aa _ caab _ c _ abb _ c
cccbb _ aa _ cc _ bbbaa _ c
_ bc _ _ bb _ aabc