The correct answer is B. Phosphatidylethanol (a serum test) is more sensitive than CDT in detecting sustained heavy alcohol consumption, while urinary ethyl sulfate and glucuronide may be best utilized to detect binge drinking (they stay positive for up to 90 hrs after consumption). Particularly in the transplant evaluation setting, patients might be more likely to abstain just prior to a scheduled visit/lab draw, so PEth or CDT would be preferred over the urinary biomarkers or the serum ethanol level.

Publication reference : Walther L et al. Phosphatidylethanol is superior to carbohydrate-deficient transferrin and γ-glutamyltransferase as an alcohol marker and is a reliable estimate of alcohol consumption level. Alcohol Clin Exp Res 2015; 39: 2200-8
Reference URL: https://pubmed.ncbi.nlm.nih.gov/26503066/