AMC 12 2001 Problem 5

What is the product of all positive odd integers less than 10,000 ?

Answer Choices
A. \dfrac{10000 !}{(5000 !)^{2}}
B. \dfrac{10000 !}{2^{5000}}
C. \dfrac{9999 !}{2^{5000}}
D. \dfrac{10000 !}{2^{5000} \cdot 5000 !}
E. \dfrac{5000 !}{2^{5000}}