This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Surgery, Subject name: Surgery
[{'content': 'All of the following are true about neck dissection except: \nSelect and explain. \nA. Central compament neck dissection involves removal of level VI LNs, B. Supraomohyoid neck dissection involves removal of level I-III LNs, C. Type II MRND preserves both spinal accessory nerve and sternocleidomastoid muscle, D. Lateral neck dissection: removal of level II-V lymph nodes + internal jugular vein', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Neck dissection Comprehensive neck dissection Selective neck dissection Radical neck dissection(RND): Removal of lymph nodes I-V + spinal accessory nerve(SAN) + Internal jugular vein(IJV) + sternocleidomastoid muscle(SCM) Extended radical neck dissection(ERND): Radical neck dissection + removal of one or more groups of lymph nodes, non-lymphatic structures or both Bilateral radical neck dissection Modified radical neck dissection(MRND): Removal of level I-V lymph nodes with (Mnemonic: SIS) - Type I: Preserves only SAN - Type II: preserves both SAN and IJV - Type III: preserves SAN ,IJV, SCM (Functional neck dissection) Supramohyoid neck Dissection: Removal of level I-III LNs. Extended supraomohyoid neck dissection: Removal of level I-IV LNs Posterolateral Neck dissection: Removal of level II-V LNs + Suboccipital LNs + retro auricular LNs. - Lateral neck dissection: Removal of level II-V LNs + Internal jugular vein. - Central compament neck dissection: Removal of level VI LNs', 'role': 'assistant'}]