根据《外资保险公司管理条例》和《外资保险公司管理条例实施细则》的规定，合资寿险公司中外国保险公司持股比例不得（ ）公司总股本的（ ）。

A．超过，50％

B．超过，70%

C．低于，30%

D．低于，59%

Should RGS (regulator of G protein signaling) proteins be classified as GEFs (guanine nucleotide exchange factors) or GAPs (GTPase activating proteins) Explain what role this activity plays in modulating G-protein-mediated responses in animals and yeasts.