B

Most studies, including one bearing the identical title to the question, find that the prevalence of hepatitis G virus (GB V-C) and TT virus (torque teno virus) in patients with cryptogenic chronic liver disease is similar to (or lower than) that in other liver-disease controls or blood donors, and no association with histological severity is seen [Di, 2002, PMID 11926574; Hollingsworth, 1998, PMID 9658369].