单选题图中，已知θ=0.5ω，不考虑阻尼，AB杆A端的纯强迫振动最大弯矩之值为（　　）。<br/> <br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/8325655_0.jpg"><br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/8325655_0_1.png">