Which of the following statements is FALSE regarding Ras mutations in cancer patients?

A)Mutations often occur at codons 12,13,or 61.
B)Oncogenic mutations usually result in higher levels of GDP-bound Ras.
C)Oncogenic mutations usually result in higher levels of GTP-bound Ras.
D)Cells often have compromised activity of GTPase-activating proteins GAPs).
E)None of the above.