Hard
ba_cb_b_bab_ (find the correct letters to fill the blanks)
Explanation
Explanation
The complete series follows a repeating 4-letter cycle: b,a,b,c (i.e., 'babc' repeated). Filling in the blank positions according to this cycle gives 'bacc'.
PRO TIP
Re-check your working by substituting the answer back into the original question.