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: Medicine
Prions diseases are-a) Alzheimer's diseaseb) Gerstmann straussler Scheinkan syndromec) Familial Fatal insomniad) Frontotempotal dementiae) Creutz- feldt Jakob disease 
Select and explain. 
A. ab, B. bc, C. bce, D. ace
C: bce
Answer: C: bce 
Explanation: None