Which carcinogen had he likely been exposed to?

A 69-year-old male patient presents to the oncology clinic with a 3-months history of right upper quadrant discomfort, weight loss and anorexia. Ultrasound liver raises the suspicion of a hepatocellular carcinoma.

Which carcinogen had he likely been exposed to?

Nitrosamine

Aflatoxin

Aniline dye

Arsenic

Benzene