单选题以下临空处防护栏杆做法中，栏杆高度须从下剖翻边顶部计算的是（　　）。<br/> A．<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251122/18930117_0.jpg"><br/> B．<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251122/18930117_0_1.jpg"><br/> C．<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251122/18930117_0_2.jpg"><br/> D．<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251122/18930117_0_3.jpg">