Correct answer = C.
<p>  The pathology of IPF demonstrates areas
     of normal lung parenchyma, areas of active inflammation, and
     areas of end-stage fibrotic lung all within the same patient
     at the same point in time.  Hence, transbronchial biopsy, with
     the small quantity of lung tissue obtained and the high
     likelihood of a sampling error, is often inadequate for
     diagnosing IPF and open-lung biopsy is often required.  High
     resolution CT shows a characteristic pattern of bibasilar
     peripheral fibrosis with or without evidence of alveolar
     inflammation; typically there is no pleural involvement and no
     pleural effusion.  Treatment with steroids and/or cytotoxic
     agents is indicated if there is evidence of active
     inflammation or a rapidly deteriorating course, although the
     benefit of such therapy is largely unproven.