A 67-Year-Old Woman Comes to the Office Complaining of Vomiting

A 67-year-old woman comes to the office complaining of vomiting for the past several months. The vomiting is associated with postprandial crampy abdominal pain. The vomiting has bilious character. During the past 3 months, the patient lost 15 lbs. Physical examination was unremarkable. A CT scan with contrast of the abdomen reveals a mass in the transverse portion of the duodenum that is infiltrating the surrounding tissues. Which of the following structures is at risk for compression by this tumor?

A) Common bile duct
B) Gastroduodenal artery
C) Portal vein
D) Superior mesenteric artery
E) Ureter