Ans. is 'd' i.e., T4N3 [Ref: Schwartz 9th/e p491; Here's the TNM staging for Oral cavity carcinoma (according to TNM ?h edition) Primary tumor staging of oral cavity carcinoma T0 No evidence of primary tumor T1 Tumor is <2 cm in greatest dimension T2 Tumor is > 2 cm and < 4 cm in greatest dimension T3 Tumor > 4 cm in greatest dimension T4a (lip) Primary tumor invading cortical bone, inferior alveolar nerve, floor of mouth, or skin of face (e.g., nose or chin) T4a (oral cavity) Tumor invades adjacent structures (e.g., cortical bone, into deep tongue musculature, maxillary sinus) or skin of face T4b (lip & oral) Tumor invades masticator space, pterygoid plates, or skull base and/or encases the interna carotid artery Regional lymphadenopathv NX Unable to assess regional lymph nodes N0 No evidence of regional metastasis N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2a Metastasis in single ipsilaeral lymph node, > 3 cm and < 6 cm N2b Metastasis in midtiple N2c Metastasis in bilateral or contralateral lymph nodes, all nodes < 6 cm N3 Metastasis in a lymph node > 6 cm in greatest dimension Note: midline nodes are considered ipsilateral nodes.