Which Statement Is Not True About Retroviruses (RNA Tumor Viruses)

Which statement is not true about retroviruses (RNA tumor viruses) .

A) Study of the oncogenes carried by retroviruses has led to major advances inunderstanding of the molecular basis of cancer.
B) Most human cancers are the result of a retroviral infection.
C) When a retrovirus infects a cell, its RNA genome is converted to DNA by the viral-encoded reverse transcriptase.
D) Occasionally retroviruses acquire a gene from the host that is normally involved in cellulargrowth control.