The hottest continent, Africa has a lot of resources, ______ are still undeveloped.

A．many of them

B．many of whom

C．many of it

D．many of which

患者女性，59岁。慢性胆囊炎、胆石症急性发作。高血压、冠心病（心绞痛）10年，ECG示冠状动脉供血不足，心率66次/分，血压185/100mmHg。行胆囊切除加胆总管探查T形管引流术，术中处理胆囊时突然心率减慢、室性二联律。

最好的麻醉方法是（）

A.局麻+强化

B.腰麻

C.连续硬膜外阻滞

D.全麻气管内插管

E.针刺麻醉