
如图,在\(\triangle ABC\)中,\(AB=AC=2\),\(BC= \sqrt {2}\),且\(A\)在平面\(α\)上,\(B\)、\(C\)在平面\(α\)的同侧,\(M\)为\(BC\)的中点,若\(\triangle ABC\)在平面\(α\)上的射影是以\(A\)为直角顶点的\(\triangle AB′C′\),则\(AM\)与平面\(α\)所成角的正弦值的取值范围是\((\) \()\)
A. \([ \dfrac { \sqrt {42}}{7},1)\)
B. \([ \dfrac { \sqrt {42}}{7},1]\) C. \([ \dfrac { \sqrt {42}}{7}, \dfrac { \sqrt {14}}{4}]\) D. \([ \dfrac { \sqrt {42}}{7}, \dfrac { \sqrt {14}}{4})\)