After Cytologic Examination a Patient Is Diagnosed with a Tumor

After cytologic examination a patient is diagnosed with a tumor that is staged as T_IS, N_1a, M₀. What does this staging classification indicate to the nurse about the patient's tumor?

A) T_IS means the tumor is in situ.
B) M₀ means that it has metastasized.
C) M₀ means that it has not metastasized.
D) N_1a means one lymph node is involved.
E) N_1a means that no lymph nodes are involved.