The old man sitting opposite me cleared his throat as if ________ something. [ ]

A．said  

B．to say

C．having said  

D．saying

老年肾虚，大便秘结，小便清长，头目眩晕，腰膝酸软。治疗应选用（）。

A.肾气丸

B.济川煎

C.真武汤

D.地黄饮子

E.六味地黄丸