[单选题]
The graph shows the variation orgtua3 5-qsb6.mt+om hk2,li f the toc*cx moj s5 bobv:)u9wn36* ixtal electric potential due to two point electriuooimbs*: w5x* cjb9c)6n3x v c charges $q_1$ 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 $\frac{q_1}{q_2}$
