I do know that it takes 3 100's to bring one 0 to a "C". Knowing that, I would not advise getting any zeroes.
The information that I would need to know to correctly answer your question is: How many assignments have you already had to get your "A".
For instance if you had:
3 assignments of 100 each ...
3 x 100 = 300
300 / 3 = 100%
But now with one 0:
Those same 3 assignments of 100 each AND that one 0 ...
3 x 100 = 300
300 / 4 = 75%
which is a drop of 25 points for one zero.
Now, if you had 10 assignments of 100 each ...
10 x 100 = 1,000
1,000 / 10 = 100%
But those same 10 assignments of 100 each AND that one 0 ...
10 x 100 = 1,000
1,000 / 11 = 90.9 or 91%
which is a drop of 9 points for one zero.
Taking one zero is a gamble based on if you have many assignments (low risk) or a few assignment (high risk) of altering your final average for a class.
Hope this was helpful!