B. 11
Feedback There are three parallel series going on in this question. The 1st, 4th, 7th terms are using the logic of -1, 2nd, 5th and 8th terms are using the logic of +1 and 3rd, 6th and 9th
erms are using the logic of +1 again. The answer will be 11, which belongs to 1st, 4th and 7th term.