<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 53-year-old woman presents to her primary care doctor due to discolored, itchy skin, joint pain, and a feeling of abdominal fullness for the past week. Her medical history includes anxiety and depression. She also experiences occasional headaches and dizziness. Of note, the patient recently returned from an expedition to Alaska, where her and her group ate polar bear liver. Physical examination shows dry skin with evidence of excoriation and mild hepatosplenomegaly. Lab investigations reveal an alkaline phosphatase level of 35 UL and total bilirubin of 0.4 mgdL. Which of the following tests is most likely to uncover the etiology of her condition?? A: Antimitochondrial antibodies, B: BRCA2 gene mutation, C: Elevated hepatic venous pressure gradient, D: Jejunal biopsy, E: Plasma retinol levels,  <response>: Based on the patients symptoms of itchy skin, joint pain, abdominal fullness, and hepatosplenomegaly after eating polar bear liver, the most likely diagnosis is vitamin A toxicity. Eating polar bear liver can cause hypervitaminosis A due to the extremely high levels of vitamin A in the liver. The key lab finding is an alkaline phosphatase level of 35 UL, which is low and can be seen in vitamin A toxicity. The test most likely to confirm the diagnosis is plasma retinol levels, which will be elevated in vitamin A toxicity. Antimitochondrial antibodies are associated with primary biliary cholangitis. BRCA2 testing is for hereditary breastovarian cancer. Elevated hepatic venous pressure gradient indicates portal hypertension. Jejunal biopsy is useful for diagnosing celiac disease but does not relate to the patients symptoms.E: Plasma retinol levels 