13. If the value of net assets for a firm equal 180,000 JD at Jan, 1, 2008 then it becomes 220,000 JD at Dec, 31, 2008. The value of net assets needed to maintain the productive capacity value equals 190,000 JD. And the price index level increased by 15%. Find the income of the firm according to the concept of maintenance the purchasing for productive capacity. (2 Points) * a) - 17000 b) 13000 c) 1500 d) 30000