椭圆两焦点分别为\( {F}_{1}(-1,0),{F}_{2}(1,0),\)点P在椭圆上\( ,\)且\( \left|P{F}_{1}\right|,{\text{|F}}_{1}{F}_{2}|,|P{F}_{2}|\)成等差数列\( ,\)则此椭圆方程为 ( )
A.\( \frac{{x}^{2}}{5}+\frac{{y}^{2}}{4}=1\)
B.\( \frac{{x}^{2}}{4}+\frac{{y}^{2}}{5}=1\) C.\( \frac{{x}^{2}}{4}+\frac{{y}^{2}}{3}=1\) D.\( \frac{{x}^{2}}{3}+\frac{{y}^{2}}{4}=1\)