The Viral Raf Oncogene Produces a Constitutively Active Protein Because

The viral raf oncogene produces a constitutively active protein because the

A) gene is always on.
B) kinase domain is mutant and cannot be competitively inhibited.
C) regulatory domain has been replaced by viral sequences so the protein cannot be turned off.
D) GTPase activity is deficient and the protein is always in the GTP form.