It is difficult to imagine his _____ the decision without any consideration.

A．accept

B．accepting

C．to accept

D．accepted

根据《客运专线铁路无碴轨道铺设条件评估技术指南》的要求，沉降变形观测网按（）等变形测量等级技术要求建立，沉降变形观测点的水准测量采用（）等变形观测测量技术要求。

A.三；二

B.二；三

C.三；四