In alphabet series, some alphabets are missing which are given in that order as one of the alternatives below it. Choose the correct alternative.
_ abb _ _ bb _ a _ bbab _ ba
_ bc _ _ bb _ aabc
ba _ b _ aabb _ a _ _ a _ bb
b _ b _ bb _ _ bbb _ bb _ b
ab _ aa _ caab _ c _ abb _ c
a _ c _ abb _ a _ bc _ bc _ ab