【单选题】5 / 9纯扭截面尺寸验算公式为?AT≤0.25βcfcWtT \le 0.25 \beta_c f_c W_tT≤0.25βcfcWt正确BT≤0.7ftumh0T \le 0.7 f_t u_m h_0T≤0.7ftumh0CT≤fyAstlT \le f_y A_{stl}T≤fyAstlDT≤0.35fcbhT \le 0.35 f_c b hT≤0.35fcbh参考答案A参考解析T≤0.25βcfcWtT \le 0.25 \beta_c f_c W_tT≤0.25βcfcWt。