请各位老师及高人写一下解此题的思路.我不清楚如何解此题.谢谢

In 2005, Bethel Security Inc. reports pretax income of 180 million and an effective tax rate of 15 percent. It is the first time in four years that the company has reported a profit. In the footnotes to the financial statements the company also discloses that the valuation  allowance associated with a deferred tax asset decreased from 87 million to 32 million as a result of the utilization of tax-loss carryforwards. Net income appropriately adjusted for the change in the valuation allowance is closet to

A.      0 million

B.      55 million

C.      74 million

D.     98 millioin

这是二级的。在book 3, finanacial analysis 里面的analysis of income tax  那一节后面的练习