This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
Structures preserved in functional radical dissection of the neck -a) Int. jugular veinb) Sternomastoidc) Lymph nodesd) Accessory nerve 
Select and explain. 
A. abc, B. bcd, C. abd, D. acd
C: abd
Answer: C: abd 
Explanation: Functional dissection is modified radical neck dissection (MRND Type III ) Modified radical neck dissection is done only selected cases where tumor is very well differentiated and less aggressive like in papillary carcinoma of thyroid with lymph node secondaries . Structures preserved here are sternomastoid muscle , internal jugular vein and spinal accessory nerve . Ref - Srb's manual of surgery 5/e p450