B

Stage T3 N2 M0 oral cavity squamous-cell carcinoma is stage IVA, a high-risk, resectable disease. Current guidelines recommend wide surgical excision with neck dissection followed by postoperative radiotherapy (with or without concurrent chemotherapy) to control the primary tumor and involved nodes. Studies show that surgery plus adjuvant RT gives better survival than surgery alone or non-surgical approaches in stage III/IVA oral cancers [Kravets 2020, PMID 32996744; Gore 2015, PMID 24532246].