[单选题]
Suppose that the speed of an electb/dc6 bo 8yy6k(i7 ralron traveling 2000 m/s is known tb3ie3f5 i 6kyytn*1ifo an accuracy of kfyi1t5fi *e 3yibn631 part in $10^5$ (i.e., within 0.001%). What is the greatest possible accuracy within which we can determine the position of this electron?
A. $2.9 \; mm$
B. $5.8 \; mm$
C. $8.7 \; mm$
D. $1.2 \; cm$