已知双曲\( \frac{{x}^{2}}{{a}^{2}}-\frac{{y}^{2}}{{b}^{2}}=1(a>0,b>0)\)的焦距为10\( ,\)一条渐近线为\( y=\frac{1}{2}x\)则该双曲线的方程为 ( )
A. \( \frac{{x}^{2}}{20}-\frac{{y}^{2}}{5}=1\)
B. \( \frac{{x}^{2}}{5}-\frac{{y}^{2}}{20}=1\) C. \( \mathrm{ }\frac{{x}^{2}}{80}-\frac{{y}^{2}}{20}=1\) D. \( \mathrm{ }\frac{{x}^{2}}{20}-\frac{{y}^{2}}{80}=1\)