A $6.9 \mu \mathrm { C }$ Negative Point Charge Has a Positively Charged Particle in an Has

A $6.9 \mu \mathrm { C }$ negative point charge has a positively charged particle in an elliptical orbit about it. If the mass of the positively charged particle is $1.0 \mu \mathrm { g }$ and its distance from the point charge varies from $4.0 \mathrm {~mm}$ to $16.0 \mathrm {~mm}$ , what is the maximum potential difference through which the positive object moves? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

A) $- 5.2 \mathrm { MV }$
B) $19 \mathrm { MV }$
C) $3.9 \mathrm { MV }$
D) $12 \mathrm { MV }$