设点\(P\)为椭圆\(C： \dfrac {x^{2}}{25}+ \dfrac {y^{2}}{16}=1\)上一点，\(F _{1}\)、\(F _{2}\)分别是椭圆\(C\)的左、右焦点，且\(\triangle PF _{1} F _{2}\)的重心为点\(G\)，如果\(|PF _{1} |\)：\(|PF _{2} |=2\)：\(3\)，那么\(\triangle GPF _{1}\)的面积为\((\:\:\:\:)\)
A. \( \dfrac {4 \sqrt {2}}{3}\)
B. \(2 \sqrt {2}\) C. \( \dfrac {8 \sqrt {2}}{3}\) D. \(3 \sqrt {2}\)
