This question is _______ more difficult than that one [ ]

A. many

B. much

C. very

D. a few

称为"一源三歧"的经脉是：

A．任脉、督脉、带脉

B．任脉、冲脉、带脉

C．督脉、冲脉、带脉

D．任脉、督脉、冲脉

E．任脉、阴跷脉、阴维脉