16.(2023•迎江区校级模拟)已知点DDD为锐角ΔABC\Delta ABCΔABC的外接圆OOO上任意一点,AB=2AB=2AB=2,AC=4AC=4AC=4,则(AC→−OC→)⋅BD→(\overrightarrow{AC}-\overrightarrow{OC})\cdot \overrightarrow{BD}(AC−OC)⋅BD的取值范围为((( )))