This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Common about tumors of PNS and Nasal Ca-a) Sq cell Ca is the M.C. typeb) Adeno Ca is the M.C typec) Melanoma can occurd) Adeno cystic Ca 
Select and explain. 
A. a, B. bc, C. ac, D. b
C: ac
Answer: C: ac 
Explanation: None