Q. A 55-year-old male presents to your clinic with a complaint of abdominal pain for the past two months. He reports that the pain is constant and is located in the upper right side of his abdomen. He also reports a loss of appetite and a 10-pound weight loss over the past two months. Physical examination reveals a tender abdomen and jaundice. Further laboratory tests show elevated liver function tests and elevated bilirubin levels. You order an ultrasound, which shows dilated bile ducts and a mass in the region of the bile ducts. Given the findings, you order a follow-up CT scan of his abdomen, which shows a mass in the perihilar region, consistent with a cholangiocarcinoma. A biopsy is performed and confirms the diagnosis. The patient is referred to a gastroenterologist for further management. A detailed evaluation of the bile ducts is performed using endoscopic retrograde cholangiopancreatography (ERCP), which confirms the diagnosis and determines the tumor to be a Type IV cholangiocarcinoma by the Bismuth-Corlette classification system. The patient is then referred to a surgical oncologist, who recommends a resection of the bile duct and liver. Based on the information you have at this point in time, which of the following most accurately describes the location of this patient’s tumor?