1997 Pascal Problem 18

The product of 20^{50} and 50^{20} is written as an integer in expanded form. The number of zeros at the end of the resulting integer is

\textbf{(A)}\ 70\quad \textbf{(B)}\ 71\quad \textbf{(C)}\ 90\quad \textbf{(D)}\ 140\quad \textbf{(E)}\ 210

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Pascal contests here.