The given series is: ba_ba_bac_acb_cbac

To find the next term in the series, let's analyze the pattern:

1. The first term is "ba".
2. The second term is the same as the first term, "ba".
3. The third term is obtained by adding the next letter in the alphabet after 'b' to the second term, resulting in "bac".
4. The fourth term is obtained by rearranging the letters in the third term, resulting in "acb".
5. The fifth term is obtained by adding the next letter in the alphabet after 'c' to the fourth term, resulting in "cbac".

Based on this pattern, we can see that the series alternates between repeating the previous term and adding the next letter in the alphabet to the previous term. Let's continue this pattern to find the next term:

6. The sixth term is obtained by rearranging the letters in the fifth term, resulting in "acbc".
7. The seventh term is obtained by adding the next letter in the alphabet after 'c' to the sixth term, resulting in "cbaca".

Therefore, the next term in the series is "cbaca".

Now let's check the given options:

a) aacb - This option does not follow the pattern of the given series.
b) bbca - This option does not follow the pattern of the given series.
c) ccba - This option matches the next term in the series. The correct answer is option 'C'.
d) cbac - This option is the fifth term in the series, not the next term.

Therefore, the correct answer is option 'C' - ccba.

C ans