A 40-year-old man presents with right upper quadrant pain, generalized weakness, and weight loss. He gives a past history of hepatitis B infection. On examination, he has hepatomegaly; there are arterial bruits, ascites, jaundice, and signs of cirrhosis. What investigation would you value most in the diagnosis of this patient?

A) Human chorionic gonadotrophin
B) α-fetoprotein
C) Carcinoembryonic antigen
D) Alkaline phosphate
E) S-100 antigen