This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Vectors for Plague transmission 
Select and explain. 
A. X. cheopis, B. X. astia, C. Pulex irritans, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: The commonest and the most efficient vector of plague is the rat flea , X. cheopis, but other fleas may also transmit the infection, e.g., X. astia, X. brasiliensis and Pulex irritans(human flea). Both sexes of the flea bite and transmit the disease. Ref: Pg No:320;park Textbook ,25th Edition