在棱长为2的正方体中,M、N分别为棱AA´和BB´的中点,若θ为直线CM与D´N所成的角,则sinθ=( )
A <img width="18" height="37" src="https://www.beizhujiaoyu.com/uploads/202208/20190918212131_5109.png" /> B <img width="35" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20190918212131_7453.png" /> C <img width="18" height="37" src="https://www.beizhujiaoyu.com/uploads/202208/20190918212133_6672.png" /> D <img width="36" height="41" src="https://www.beizhujiaoyu.com/uploads/202208/20190918212133_8703.png" />