[单选题]
The graph shows the van ux+ 4ey axtucer1;t q225-dlriationx8l m(i5mwwd n(wl-8lq 2.meo of the total electric potential due to two point electric cln8 -i82 x5lmq.dmowwm(lw( eharges $q_1$ and $q_2$ located 4.0m apart. The distance r is defined to be zero at the location of $q_1$.
What is the ratio of $\frac{q_1}{q_2}$
