—Will you stay for some more days?

—Sorry, I _______. My mother called to ask me to go back at once. [ ]

A. mustn't

B. may not

C. can't

D. wouldn't

如图所示某山区拟建一座尾矿堆积坝，堆积坝采用尾矿细砂分层压实而成，尾矿的内摩擦角为36°，设计坝体下游坡面坡度α=25°。随着库内水位逐渐上升，坝下游坡面下部会有水顺坡渗出，尾矿细砂的饱和重度为22kN/m³，水下内摩擦角33°。试问坝体下游坡面渗水前后的稳定系数最接近下列哪个选项？（）

A.1.56，0.76

B.1.56，1.39

C.1.39，1.12

D.1.12，0.76