The number of bijective functions \( f:\{1,3,5,7,\ldots,99\}\to\{2,4,6,8,\ldots,100\} \), such that \( f(3)\ge f(9)\ge f(21)\ge \ldots \ge f(99) \), is ______________.
\( {}^{50}P_{17} \)
\( {}^{50}P_{33} \)
\( 33!\times 17! \)
\( \dfrac{50!}{2} \)