A. 8

B. 10

C. 11

**D. 12 (Correct)**

Explanation:

Suppose he has 100 items. Let C.P. of each item be Re. 1.

Total cost = Rs. 100. Number of items left after theft = 80.

S.P. of each item = Rs. 1.10

Total sale = 1.10 * 80 = Rs. 88

Hence, loss % = 12/100 * 100 = 12%