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: Social & Preventive Medicine
Carrier stage seen in -a)  Poliob)  Cholerac)  Pertusis d) Plague e)  Tetanus 
Select and explain. 
A. da, B. abc, C. dea, D. ac
B: abc
Answer: B: abc 
Explanation: None