与水肿关系最为密切的脏腑是（）。

A．肺、脾、肾

B．肺、胃、肾

C．心、脾、肾

D．肝、脾、肾

E．心、肝、肾

An unstable upright equilibrium position on a vessel means that the mrtacenter is（）.

A.lower than the center of gravity

B.at the same height as the center of gravity

C.heigher than the baseline

D.on the longitudinal centerline