求助：财报分析Notes331页的一道题

Taking an impairment charge due to a decrease in the value of a long-lived depreciable asset is least likely,in the period the impairment is recognized ,to reduce a firm's:
  A net income
  B operating income
  C taxes payable

答案是C，我觉得没问题。但是B选项，Impairment应该属于Unusual or infrequent items，是否会影响operating income呢？
如果是Extroadinary items的话是肯定不会放在Operating income 里面的吧（GAAP）。请各位达人指点一下。

The impairment loss is an expense in the income statement (unless it relates to a revalued asset where the value changes are recognised directly in equity). [IAS 36.60]
should not be considered as Unusual or infrequent items