Projectile motion of charged particle 3

The above shows the moving path of a charged particle with quantity of electric charge $Q,$ along the three points $A$ , $B$ and $C$ on a parabola. The blue dotted lines are isoelectric lines, and the electric potential of the points $A$ , $B$ and $C$ are $2$ V, $4$ V and $0$ V, respectively. Which of the following statements is correct? (The force acting on the charged particle is electric force only, and ignore the generaion of electromagnetic waves.)

a) The charged particle has a positive charge.

b) The acceleration of the charged particle at point $B$ is zero.

c) The work done by the electric force on the charged particle when it moves from point $A$ to point $C$ is $6$ Q.