The selfless village doctor treated whoever came to his family without any _____. [ ]

A. cost                

B. charge              

C. payment            

D. price

已知细菌毒素中毒性最强的是（）

A.破伤风痉挛毒素

B.霍乱肠毒素

C.肉毒毒素

D.金葡菌肠毒素

E.氰化钾