Which statement best describes Light's criteria for distinguishing exudative from transudative pleural effusions?

• A. All three thresholds must be met to categorize as exudate.
• B. Any one of the three thresholds must be met: pleural/serum protein ratio > 0.5, pleural/serum LDH ratio > 0.6, or pleural LDH greater than two-thirds the ULN.
• C. Only the pleural/serum protein ratio matters.
• D. Pleural LDH alone determines exudate.

Answer: (B)