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 _ bbb _ _ abbbb _ abbb _
ab _ aa _ bbb _ aaa _ bbba
b _ b _ bb _ _ bbb _ bb _ b
a _ abbb _ ccccd _ ddccc _ bb _ ba
a _ cdaab _ cc _ daa _ bbb _ ccddd
aa _ ab _ _ aaa _ a