Superposition Principle and Continuous Charge Distribution

A charge $Q_1$ exerts some force on a second charge $Q_2.$ If a third charge $Q_3$ is brought near, the force of $Q_1$ exerted on $Q_2$:

There is a uniform spherically symmetric surface charge density at a distance $R_0$ from the origin. The charge distribution is initially at rest and starts expanding because of mutual repulsion. The figure that represents best the speed $V\left(R\left(t\right)\right)$ of the distribution as a function of its instantaneous radius $R\left(t\right)$ is: