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: Dental
Acantholytic cells area) Epidermal cellsb) Plasma cellsc) Keratinocytesd) Giant cells 
Select and explain. 
A. a, B. bc, C. ad, D. ac
D: ac
Answer: D: ac 
Explanation: Acantholytic cells (Tzank cells) are separated keratinocytes, the major epidermal cells.