【单选题】137 / 558单筋截面MuM_uMu的常用表达式是( )。AMu=fyAs(h0−x/2)M_u = f_y A_s (h_0 - x/2)Mu=fyAs(h0−x/2)正确BMu=fyAsh0M_u = f_y A_s h_0Mu=fyAsh0CMu=α1fcbhM_u = \alpha_1 f_c b hMu=α1fcbhDMu=Vh0M_u = V h_0Mu=Vh0参考答案A参考解析Mu 由内力臂 h₀−x/2 决定。