在长方体\(ABCD-A _{1} B _{1} C _{1} D _{1}\)中，\(AB=1,AD= \sqrt {2},AA_{1}= \sqrt {3}\)，则直线\(DD _{1}\)与平面\(ABC _{1}\)所成角的余弦值为\((\:\:\:\:)\)
A. \( \dfrac { \sqrt {3}}{2}\)
B. \( \dfrac { \sqrt {3}}{3}\) C. \( \dfrac { \sqrt {15}}{5}\) D. \( \dfrac { \sqrt {10}}{5}\)
